Oh just some thoughts on the stamping of the numbers.

I think that the numbers on the bottom of the grip are stamped all at one. It does not look like it was a hammer blow on metal stamps. It was probably done in a press. With out knowing what they used there are two common ways that this is done.

The one way to to have a holder in the press and the operator inserts the numbers and letters that are need for each gun. This is very easy to make mistakes as the stamps come out and can be inserted out of order, IE VS or SV, just reverse the stamps. What happens is that since the number and letters are reverse images and the head is upside down mistakes are easy to make and are found after you make the stamp.

The other method is to use whats called a "Numberall" head. This unit has the number stamps on round disks that spin snap in place at each number. Kind like a car odometer, or how odometers were (These are not roll marks but stamps). These units are often custom made so it would have the letters and numbers needed. These heads can be made to auto index so that after a press stroke it clicks over the next number with out the operator touching it, or forgetting to do it.

I know on manufacturer using a numberall for sure

They do not use the auto index because they want to be sure the stamp is good deep and clear, if not, rehit it or scrap it and make a replacement with that SN, no SN gaps.

From my experience serial numbering is an important step and its not taken lightly. The parts have a lot of value at this point and they dont want to scrap them.