101% definite that it's a hand cut typeface. With that said, you could pretty much do what you want for a date cutting, so long as it's close to what's already there.
There are significant differences between the same characters, and that's to be expected. Your only challenge will be to hand work (chisel) the panels to resemble the existing.
With that said, there seems to be a lot more hand tooled memorials in Europe than the US, with each reflecting the individual talents of each artisan, and I like that. Everything here in the US typically looks identical. I'm personally rebelling against those "cookie cutter" shops by offering natural boulder memorials...and no two ever look the same.
JB