5088 Starter question

[ThirdGenRed]

I'm working on a 1985 5088 SN8647, and it has a Delco Remy 10 tooth starter on it. The earlier  1981-1983 5088s used a Delco Remy 12 tooth starter that I believe used a center of case centerline, while the later 5088 Delco Remy 10 tooth starter used a 2.5mm offset centerline. The later 10 tooth starter is a bit of an oddball, hard to find a new, not rebuilt one, the earlier 12 tooth starter is more common. Are these starters interchangeable?  And if they are interchangeable, why did they change to the 10 tooth?

[Thesd5488]

I think they all interchangeable but not 100% suy

[ThirdGenRed]

They both have the SAE 3 bolt pattern and I saw that they only list a 138 tooth flywheel, so I assumed they interchange, but wanted to be sure. I would guess they offset the centerline of the 10 tooth starter because the diameter of the 10 tooth gear would have to be a smaller diameter and being a smaller diameter, it needed to be closer to the ring gear, and I am guessing the 10 tooth might have more torque because of the smaller diameter of the 10 tooth gear due to gear reduction? Just guessing about that though.  I was actually surprised there was a 10 tooth and 12 tooth starter, I thought the 5X88 series all used the same starter, I guess I learned something new. I don't remember anyone posting anything about the 5X88 using two different starters in the production run like you could damage the flywheel ring gear by using the wrong starter, but just wanted to verify before I put in a new 12 tooth starter and damaged something and it was a known fact to not do that.