Well, I promised .
The Mamiya 645 lenses can be divided into two basic types:
1) The lenses that work only with the auto-focus film bodies; and
2) The manual focus lenses that work fully featured on all the manual focus bodies, and with reduced metering convenience on the auto-focus film bodies.
Your 1000s is from the very first series of Mamiya 645s, and is of course manual focus.
So you have a very wide selection of lenses to choose from. You cannot, however, use lenses designed for the RB67, the RZ67, the TLRs (C3, C33, C330, C220 etc.) or the Mamiya rangefinders (6 or 7).
The initial 645 lenses are designated with a "C" designation only. They are quite good, but getting to be quite old, and in some cases the lens coatings arn't nearly as advanced as more modern versions.
In some cases, for some focal lengths, the "C" lenses were initially superseded by lenses with the "C" plus an additional designation of "S". The "S" designation refers to "short" (as I understand it) and featured a re-designed optical format that permits a smaller, shorter barrel. There aren't many examples of "S" lenses.
The most modern lenses still have the "C" but also have an additional "N" designation. They feature more modern coatings and more modern styling. They make less use of metal for the barrels, and more use of plastic, so tend to be lighter.
Most of the Mamiya 645 lenses have no shutter and rely exclusively on the focal plane shutter in the camera. There are, however, a few lenses that have a built-in leaf shutter, and are therefore well suited for use with fill flash. They have an "LS" designation added to their labelling. The latest, "N" versions of the leaf shutter lenses add the ability to be automatically cocked for each exposure if one has the right body, power winder and shutter cocking connectors. Otherwise, when used in leaf shutter mode, they require manual cocking for each exposure.
In some cases, as the lenses have evolved through the various versions, their optical design has changed. In other cases the optical design has remained unchanged.
In some cases, as the lenses have changed, their physical size has changed as well. The 45mm f/2.8 is a good example: the original "C" version is quite large and takes 77mm filters, while the newer "N" version is smaller and takes 67mm filters.
For some focal lengths, there are no modern "N" versions. The 70mm LS lens and the 110mm f/2.8 lenses are examples.
In at least one case, the maximum aperture available changed over time - the original 150mm f/4 lens was replaced with a 150mm f/3.5.
The most common lenses - 55mm f/2.8, 80mm f/2.8, 110mm f/2.8, 150mm f/3.5 and 210mm f/4 lenses all use 58mm filters and all have barrels that permit use of the focus assist lever.
Other lenses use other filter sizes and/or have thicker barrels that don't let you use the focus assist lever.
I've had a number of different bodies and lenses over time, and all the lenses I've tried have been excellent, even though I prefer some over the others.
Hope this helps.
PS: this link to an index on Mike Butkus' excellent camera manual site lists a whole bunch of Mamiya 645 resources: http://www.butkus.org/chinon/mamiya/...ccessories.htm