girard perregaux

This watch is the king of no frills, it has no second hand, and not only has no numbers, the raised gold markers are all the same !.The back is unmarked except for " 10k ".Lucky it says Girard Perregaux seahawk and Swiss on the dial.At first I thought that it was top loaded--that the movement was removed thru the crystal, but Im not even sure of that.The seahawk was introduced in 1940 and was described as having an "unclutterd dial"[no kidding].I have it on a brown crocodile strap, and it looks great. BUT I really feel silly being a "watch guy ',and not knowing a thing about it ,I hope to know at least an approximate year of manufacture. If it opens at the back you would need a microscope to see the seam.Can anyone help me with information or advice about how to find out about the watch ?
mystified in colorado, Mike H.