It looks like you have an NOS armature on the right.
As I poster earlier, if need be, AND there is enough clearance, you can gently tap the bearings further into the motor housing. You must be careful not to tap it in too far, otherwise the windings may strike the bottom of the motor housing, which will ruin them. I would use a large flat ended tool, because you do not want to distort anything on the bearing.
Your armature looks to be an NOS piece.
Be aware that a lot of Lionel parts hit the streets when everything from Madison Hardware, the Kughn collection and the Lionel (LTI) factory was sold off. A lot of those parts were factory rejects/seconds. Some of the parts I've seen were perfectly usable, others not so much.
Madison (Detroit) sold armatures by the pound. I forget how many pounds I purchased, I had a lot of armatures. I think about 1/3 were just junk with bad windings. Some just needed to have a wire soldered back onto the commutator. Some had bent shafts, others were fine.
