IANAD - but have been an ARRT ‘registered X-ray Tech’ for over 20 years and done plenty of Ultrasounds, MRI’s, CT’s, and NucMed studies (along with hundreds of ERCP’s) so I have a bit of background on gallbladder symptoms
I am not meaning this to be ‘advice-to-follow’ in your particular situation, but more of a general insight from what I have seen in my hands-ons with folks and also chatting with them about their symptoms, etc. Any Tech worth their ‘registry’ should always chat about symptoms just in case some little pearl/nugget-of-info mighta been missed that would lead to doing something beyond ‘standard’ images/protocols, so to speak. No patient is exactly the same, of course, and I have seen ‘strong men’ taken down by the tiniest of stones/blockages, and have seen HUGE packed-with-stones ducts/bladders giving zero symptoms of indicating the Gall bladder.
Tumors/other pathologies around/near the ducts can also give similar symptoms, but typically more subtly, so imaging MUST be done appropriately (etc, etc) with appropriate lab tests. A Chem12 is a ‘bundled’ set of tests (12, obviously) that look at basic chemicals/values within a body that can help narrow down the focus of diagnosis. Call it a great start. Oftentimes, that bundle can be called other names like CMP or BMP or whatever that facility/lab chooses (Complete/Basic Metabolic Profile, etc). Just saying as ‘general info’ for those who see those terms on med bills 
Just wanted to wish ya well & best-of-luck, Mama Zappa - and that major complications from Lap Choles seem to be pretty rare (usually straightforward procedure overall, IME in op-rooms). Nothing to fear but fear itself if cliches are appreciated
I do agree with the gist of most everything spoken of above…but do want to mention that zero-fat meals can be MUCH easier (less painful) than low-fat’s…but follow the Doc’s words, of course. Gallbladder’s tend to ‘contract’ to expel bile to aid in digesting fatty foods post-ingestion (its the function of the bladder to store the bile, 'eh?). When an irritated bladder moves (or crunches down upon) stones/gritty-sludge, it gets painful…obviously. A function of some/most gallbladder imaging-tests involves doing images/measurements both before and after a ‘fatty-meal’ (milkshake, greasy eggs, whatever works for patient). I’ve used Cholecystokinin (sp? aka->CCK) intravenously in Nuclear scans (termed HIDA scans, fwiw) to force ‘contractions’ to eval emptying/duct patency. If there is blockage in the duct, the pain begins almost immediately - but I sure disliked causing (often intense) pain to gain an answer. However, I could tell then and there if those ducts were blocked, and patient had a pretty good idea as well 
You might have an interest in obtaining copies of the video made during the Lap Chole, and/or the X-ray(s) done post-injection of ‘X-ray dye’ (iodinated contrast media, per se) into the proximal ductwork to verify patency, etc prior to finishing the surgery. Not all the surgeries are video’d and not all do the X-ray, but IME, it was/is pretty standard. The video can be very enlightening to understanding the procedure.
Again, hope all goes well (and love any reference to Zappa!). One more thing - most persons would be surprised at how many folks have ‘silent stones’ somewhere in their body. No such thing as a perfect person 
One more one more - I have done MRI scans on persons with ‘clips’ from LapChole (laparoscopic cholecystectomy), but it all depends on the strength of magnet (Tesla value) and the type of clip, plus the type/length of pulses used for scanning…its not always cut and dry decision as far as the MRI goes as risk-v-benefit in emergent situations comes into play also. Most MRI depts should have a listing of acceptable clips, etc and there is a very wide range of clips out there. Newer ones are certainly more amenable to MRI fields, but its a good idea to get the exact clip type from surgeon for future reference…