each machinist has his own set of tools, and they are very often not company supplied. so- if two different craftsman were involved - different stamps would be used. And even for one man - he may have mixed stamps- I have some of my grandfathers stamps- they don't all match and there is more than one of some digits. I assume as they wore out or were lost other sets or individual stamps were added. I think we have seen that odd 4 with the light strike on the upper left on other guns

The case looks pretty far gone to me. Long time PGCA member Kevin McCormack does case repair and would be the person to contact.

Yes Rick, we have seen that stamp on dozens of other Parkers.

Here's another case of a stamp from another set being used by the same gunsmith.
The first picture is the engraved trigger guard. Then the stamped water table, fore end iron, barrel, and dolls head.
Note also that the whole number is stamped on the dolls head.

After looking at a few other lifters of that era, 524 is the order number and the odd looking 4 is the barrel weight before striking. Four lbs. and no ounces seems about right for a 1-frame twelve gauge.

The mystery of that different 4 is solved in that the barrel maker of course used a different set of dies than the set used by the person who stamped the order number (524) in the right barrel flat.

right you are- i knew I had seen it- just checked my pictures - that is the same barrel weight stamp on the lifter I just sold on the board. 4lbs 14 oz on a 2 frame

And the guy stamping the barrel weights on the barrel flats with that damaged 4 die might very well have been in Belgium or Birmingham or wherever those tubes were made, married up, and weighed before shipping.