I would say it's definitely a Model 3. It matches perfectly the description and picture in West's book, page 15-21. The only anomaly not mentioned therein is the caliber of yours - .22WRF. If a factory chambering would it be rare? I don't know. I don't see evidence of a .22 Long Rifle roll stamp having been eradicated to make way for the .22WRF stamp so it's probably a factory job. Neat!

"You can lead a man to logic, but you cannot make him think." Joe Harz
"Always certain, often right." Keith McCafferty