As I understand it they were made and sold by Pentax as a budget range. I know two of the zooms also turned up with Pentax branding (no other difference) as cheap kit lenses.

The 28mm is the same as the late Pentax-M 28mm f2.8 but with different coatings, I have one and it isn't bad around f8. Colours aren't as good as the SMC Pentax 28mm f3.5 (and the Pentax-M 28/3.5) I also own though.

I'm also told that the 135mm f2.8 is a surprisingly decent lens, although the f2.5 doesn't seem hugely popular in reviews. It does seem to be part of what I can only just avoid calling ebay scams though - frequently listed with a high BIN price (as in twice what you'd pay for a good M 135mm f3.5) in the hope that people will mistake it for the SMC Pentax 135mm f2.5 (which is a completely different lens).

I have the Pentax-A 28-80 (and the F version) which were also sold as Takumar-A and -F. Avoid. They're horrible to use and the images are even worse! Mine turned up with a P30n (which I wanted) and is now mostly used as a stand for small items. Covered with a cloth it does a fine job of supporting photographic subjects! There are SMC Pentax 28-80s in both the A and F series which are much better.