Possible, but IME unlikely. Kids have an enormous ability to sort through what they hear, settling eventually on the correct sounds.
Every toddler I’ve known well (a total of sa couple dozen) has gone through stages of misprounciation. All have without any special assistance emerged successfully. And I’ve heard it said that there is no known limit to the number of “cradle” languages a baby can learn (which argues against the notion that incorrect sounds are a problem).
I checked with my mom, who is a speech pathologist, and she said, “w for /l/ and /r/ are very common substitutions especially for a 3 year-old child. Unfortunately, both /l/ and /r/ are common phonemes used in many blends but again, for a 3-year-old, it’s fine and not a concern.”
So there’s your expert consult, Frylock. Tell your wife that you’re taking her out for a nice dinner to relieve her stress about this issue with all the money you saved from going to an expert near you. However, as I believe someone mentioned upthread, I’m pretty certain there are lots of states that are required to have free testing for children. I know that my mom works with a lot of poor, urban kids, and there’s no way that some of the families she sees would be able to afford testing on their own. If your wife is still worried I can ask about testing laws in your state.