[Edward Tinker]

Costanzo did a great job, HOWEVER, every slight variation he called it a new proof or acceptance marking - realize the difference between proof and acceptance...

So, accept Costanzo as a good start but there are inaccuracies - how old is Sam's book now?

I am unsure what you are asking on the "a" suffix. Not every batch started at 1 and went to 9999 and then 1a to 9999a

so, "a" suffix would normally be the 2nd batch of 20,000 made

However, from Don and Joops book;

1940 / 42
low reported serial number 1501y and high of 8291n

100,612 made like that

you can guess at its age and Frank (who has passed on) was very good at guessing. Did you try searching the forums?
We are more than willing to help, but read the FAQ, read through the forums and it will help.

eagle 655 magazine correct, although 2 types

Ed