Mil Spec and Loaded are 2 different levels.
Mil Spec = spur hammer, original style spur grip safety, chamfered mag well, lowered ejection port. (and a few other small things)
Loaded = beaver tail grip safety, commander style hammer, a cross drilled trigger I believe, and maybe a few little details..
I added a beaver tail safety to my Mil Spec.. but in the end it would have just been cheaper to buy the Loaded straight away..