Pentax's pre AF macro lenses were generally 1:2, and require an extension to get to 1:1. I don't have any of the manual focus era macro lenses, but I do have a Pentax-F 100mm ƒ2.8 macro (1:1) lens that creates some amazing shots. It is an AF lens but works fine on manual focus cameras. It is a bit pretty pricy though. I'll probably end up with some K or M era lenses eventually. As far as the different generation lenses:
Pentax K - these were the first bayonet K mount lenses. They don't actually say Pentax-K on the lens. These are concurrent with the K1000, KX, KM, K2 cameras.
Pentax-M - Concurrent with the MX, ME, ME Super, and probably LX. Due to Pentax's move to smaller bodies, the M lenses are generally smaller lenses.
Pentax-A - these have an A selection on the Aperture dial, which is required for the camera to set aperture automatically. Concurrent with the SuperProgram Program Plus. These are the last generation of manual focus lenses from pentax.
Pentax-F - first generation of AF lenses. All have aperture rings, with A settings available.
Pentax-FA - second generation AF lenses, some are still made new. They have aperture rings with A settings.
Pentax-D FA - for full frame digital, don't usually have aperture rings, so the body has to set the aperture
Pentax-DA - for APS-C digital, no aperture ring, some actually will cover a full 35mm frame.