Those 2 guns sure look like the same engraver to my eyes.
I'll have to do some reading to see if Walt noted when the forend latch may have been changed, I was going off of my memory and that's not usually a wise thing to do
The Crass model ended at serial # 50,000 approximately, so yes, this would be somewhere in the middle of Crass production.
These models definitely have some great engraving, I should hunt more birds with them.