Welcome to the Forums Tom! Glad to have you aboard!
Thank you for your service. As long as the kit is in production, your chances are good to get the part. Some mfgrs. will even send you the entire sprue free of charge. If the kit is out of production, then after their parts supply runs out, then your luck runs out too. If it's a plane part, post your question on the aircraft section of this forum and maybe another member will be able to help you. We all have spare parts boxes. Maybe you can get lucky there.
Good Luck. Hope this helps.
Jim 
P.S. Maybe you'll be able to help someone else out with your knowledge gained while in the USAF.
Main WIP:
On the Bench: Artesania Latina (aka) Artists in the Latrine 1/75 Bluenose II
I keep hitting "escape", but I'm still here.