Chris,
Yes Wag aero has the correct spinner that is approved FAA PMA. Looks like the one on my plane. as in the link, do not over-tighten the center bolt it will twist the bracket..
https://www.wagaero.com/skull-cap-spinner-small-size-5-faa-pma-d.htmlDon't see many 150's with skull caps since they really don't look that cool but they work great without any hassles.
Although our props are not listed, I would have the mechanic install it (recheck the prop bolt torque) and do a log book entry as a minor change. A 337 filled out and mailed directly to Oklahoma never a bad idea and goes into the permanent record
the Plastic fwd bulkhead in the cone spinners don't make a lot of sense especially here in Arizona. All the plastic just becomes brittle and cracks. (age doesn't help). then it wobbles and you get cracks in the spinner..Just another avoidable problem in my eyes..
Sell your spinner on Ebay, A lot of guys have cracked ones..