Does the US military take in account military service in other countries?

There have been a few famous cases of US servicemen who have had fairly long careers in other another nations armed forces before coming to the US military (e.g. Ray Rescorla, Morgan Stanley security chief in the WTC on 9/1, or Lauri Törni the Finnish SS veteran who served in US special forces and was killed in Vietnam)

Does the US military have any policy regarding cases like this? Is the training, boot camp, etc. for someone with years of military experience identical to a kid who signs up straight out of high school?

They used to.

The Marquis de Lafayette arrived in the US colonies in 1776 with 6 years in the French military, and was promptly made an officer (eventually a general) in the US forces under George Washington.