When a Spanish shotgun was made probably has as much, or more, to do with the level of fit, finish, and extent/quality of engraving than any other factor. For a host of political, economic and cultural reasons labor in Spain was extremely cheap during the period of roughly 1945 1975. Guns made during this period will generally be better finished and have better engraving than later guns. I think thats especially true of the period roughly 1950 1970, and its true regardless of whether were talking about side locks or box locks.
In terms specifically of the insides of the locks from medium level side lock guns, the 1950s guns are much more likely to have the tool marks removed and the lock parts polished than the late 1960s guns. By the early 1960s we see more locks with tool marks removed but not polished, and by the late 1960 we are more likely to find locks with traces of tool marks left.
