I was working with my M1A sometime ago and locked the bolt to the rear.  I forgot to release the bolt when I placed it in my gun cabinet.  I think it has been like that for about two weeks.  I just found out.  Do you think there is any damage to the spring having been compressed so long?  Did I mess it up?  Thanks in advance.

There should be no problem.  

Most coil springs are designed so that their intended range of motion will never cause a set in the spring. For example, if you stretch the buffer spring in your AR or the recoil spring in your M1A longer than its resting length, or trim the follower in your mags so you can get a couple extra rounds in (allowing the spring to compress more than it was designed for) you'll have a problem.