LOL
You are spot on, a bent needle, a burr in the tip, general wear, etc. can cause issues, usually hickups with dragging fibers up from the fabric, uneven stitching, etc. Another strangly common thing like this is "needle in the right way": old straight stichers aren't fool proof, when you are new to them it's easy to get it wrong, and going from one model to another it can be very easy to make the mistake. Not all 15s are the same, and going from a 66 to a 201, I personbally need to think twice.
When you take on vintage machine expect full assembly of bobbin case and top tensioner, excessive cleaning and oiling, days of repeated efforts, thorough scraping out of groves and corners, heaps of cotton swabs,... Some times you get a nice, clean machine, but usually they always need cleaning and oiling.