I did too. I enlisted in 1960 at age 17. Did almost three years overseas, in Southeast Asia and Europe. In Dec 1963, I went to my draft board in downtown Detroit. I told the lady that I thought I might be a little bit late registering at age 21. She practically had a cow until I showed her my DD214.
And here, and I thought I was the first one to play that trick on a draft office.......Should have known. Also should have known by the lack of violent reactions! Still, great fun. Think i have that musty old dradt card somewhere, with whatever code it is........... DHS designated terrorist code on other lists.