Aside from the very early K100 tank bags, there are essentially two styles of BMW tank bags. The significant difference between these two styles is how their bases attach to the tank.
K75 (all models) and K100 (all models including the K100RS4V). This style has metal hooks at the ends of the straps that go over the seam at the bottom of the tank. The base is imprinted with what models this base will fit on.
K1, K1100RS and K1100LT. This style has brackets on each side of the tank that bolt to the tangs coming down from the sides of the tank and the straps on the tank bag base hook over those brackets. The base is imprinted with what models this base will fit on.
The mounting bracket part numbers are 71602304456(left) and 71602304457(right.)
CAUTION: Although the top sections are basically the same, these tank bags and bases can have different zippers so your best bet to ensure base-bag compatibility is to buy the tank bag and base together. For example, I have two (supposedly identical) K1100 tank bags and bases that are not cross-compatible due to their different zippers between the base and bottom of the bag.
Rain Cover: The rain cover (part 71607677284) is the same for all of these Multivario tank bags