Engine and Transmission Tech

I picked up a ford duraspark distributor on ebay the other day. Trying to figure out if I got a distributor or a core.

The good - it was advertised as a "MUSTANG 1985 5.0 -- FACTORY 302 DISTRIBUTOR WITH ROLLER CAM GEAR". And tag reads "5G 15 E5ZE 12127 BA" which appears to be referenced on a few mustang boards as an 85 mustang dizzy so seems consistent.

The maybe not good
a) the cam gear appears to have been changed because it has holes for a roll pin about 90* out from where the roll pin holding it on is. And, that extra set of holes appears to be egged a bit. Anyone know how to verify if the gear is steel? Some mustangs in this year range use cast iron. I'd hate ruin my cam if it's been changed.

b) there is a little bit of play in the shaft - like the bushing hole might be a little worn. I have a dial indicator; how much play is allowable and should I measure it at the top of the shaft where the rotor goes or at the bottom?

Depending on application, '85 Mustangs were available with cast or steel gears but I'm not sure how to identify one from the other.
If there is also some bearing play and other questionable issues, maybe it's worth trading in your distributor core on a reconditioned one from Rockauto (A-1 Cardone #302831.....w/steel gear)....$50.

That's kind of what I was thinking Graham - was just validating. Net is I think my "Great condition" eBay dizzy is actually a core. By the time I address the difficiencies I'd have more into it than using it that way.

Looks like my local AutoZone has that same Cardone part for $49.99 & will have it for me by 9am tomorrow. And AutoZone only has a $15 core charge on it.

I've been thinking about adding a spare distributor to the parts shelf - mine is an original that has never been reconditioned, so not sure when it's going to pack it in - think I'll put it on next Winter's to-do list.