I have a 56 Chevy 3100. From my understanding is there is no matching numbers in those trucks. I guess the buzz word that i was schooled is "period correct". My truck, I bought it is from the person who bought new. They only changed the parts that require routine maintenance. It has the original engine, transmission, & rear end when I bought it then sat in a field for 20 years.
Utah & Nevada do not use the engine as title number. Nevada when I had it inspected looked for the number on the frame which is stamped in two places. It does some what match the v.i.n. plate on the drivers side door jam. The motor does not match.
To sum it up for me "matching numbers" is a muscle car thing and "period correct" is how to tell what trucks came with. I was schooled if the date code on the components were within about a period of 3 months of manufacturing off the assembly line it's probably the original.
I do agree you should not stamp anything anywhere where it could confuse the DMV. It could cause a problem when registering because not all States have the same requirement. Just my .02
"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my sweet ride." -Amen
56 Chevy 3100