The bolt bodies should interchange, so long as the action length is the same. Somethings to note however: earlier Win USRAC bolt bodies had Acme thread for the bolt shroud. Later, toward the end it was switched to standard threads. FN made M70s only came with standard thread for the bolt shroud.
Additionally, USRAC M70s used the two-lever trigger which used a different striker. The FN M70s were all the three-lever MOA trigger with corresponding striker assembly. The firing pins can be used in the bolt shrouds of either Acme or standard thread, depending on what bolt body you have and what trigger you have.
Hope this helps.
AG