The door frames were all packed out with 1/4″ white oak when the house was renovated in 1900. Unfortunately that oak has since been painted & beat to hell over the years, so we are replacing it with new poplar to be painted. We ripped down the poplar on our table saw to get the right thickness & width.
Interestingly beneath the 1900 oak, there was faux painted wood grain on the original jambs. This was a very popular technique during late Victorian to make cheap woods look more exotic. The area to the right that is not painted was likely where there was a door stop.
On a side note, one improvement over past router projects, we added dust collection to the top and bottom of our router table. Milling trim makes sooooo much dust, so this upgrade has made the work much more bearable, both for breathing and cleanup.