I have the following items for sale.
Shipping $5 on any sized order to US; money back less shipping, if returned in same condition:
All lenses w/ matching (and clean) Sky or haze filter for an extra $5
1) A new Zuiko 50mm f1.8 lens (I bought this new and actually mounted it on a body once, so "demo" is probably a more apt term, but it's never left the room I keep it in) "made in Japan" "auto-S" MC ; serial # on d.o.f. ring: 3588521. A couple black specks inside (new lenses often have these), otherwise perfect. Box has price tag $129.99. I also have the spec sheet which probably came with this lens. $50 plus shipping.
2) Used Zuiko 50mm f1.8 lens lens with generic front cap and Oly rear cap. "Japan" "auto-S" MC; serial # on dof ring: 3383038. A couple specks inside, otherwise perfect. Acquired with a used body & zoom lens (which was 30-70mm). I suspect the body was only used w/ the zoom and the 50mm sat in the case. $30 plus shipping.
Note that I only want to sell one of the above two lenses and don't care much which one. I think that it is quite unlikely that there is a design change between these two lenses. More likely, when the slightly later batch needed new outer rings they just changed the wording. Actually, this has tempted me to do a side by side comparison of the two lenses, but that could take some time to get around to.
3) Soligor (for OM) 28 mm lens f2.8. 58mm filter size, MC. Light cleaning marks on front element, otherwise fine condition, but not a quality lens. Good if you are trying decide between 24 and 28 and want to play around before buying a Zuiko. I have Zuiko 24 and 35 lenses, so no need for a 28mm at all. $20 plus shipping.
4) Kenlock 1A (Skylight) filter 62 mm. Fairly clean surface, but clearly not new. No case. Not of use for Zuiko lenses, but a fairly common filter size for 3rd party lenses. I bought this by mistake (I have some 52mm filter ring lenses) $5 (no shipping cost).