If you were tried in a general court martial for wrongful appropriation, it is a felony regardless of the time you received for a sentence. If the case was tried at a special court martial, it is a misdemeanor.
If you faced charges at a summary court martial or an Article 15, [NJP], it is none of the above and should not be on your record at all.
I would suggest that you go to the nearest police department or agency that allows you to do a background check on yourself. In California, you show up with an ID, provide prints and in some circumstances, get a print out on the spot. Usually, otherwise, within 6 weeks. With any luck, that conviction, whether a general or special court martial, may not be on your record at all as the military did a poor job of imputing convictions into the national criminal index system until the mid-90s.
Get your records and if you still have questions, drop us a note.