Just to offer a little more help - I used to buy/sell old guitars and amps to enhance my collection.
I have several reference books which I haven't looked at for years which detail a couple of other ways to tell dates in both guitars and amps.
One way is to check the numbers on the pots in both guitars and amps, and also the codes on the speaker rims.
If you have a question on your stuff, go ahead and post it here or email me and I'll try to dig up the info for you.
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