My understanding is Classic was dropped a few years ago and was rebranded as YellowMark....i hear it has gone now aswell but Cat have not or atleast i have not seen anything to official on that.
I purchased a Yellowmark water pump for my 305CR excavator about two months ago. Quality seemed to be the same as original. I had to paint it though. 305CR has a Mitsubishi engine in it.
944A - Machine SN 43A2589 Engine SN 90A284
955K- Machine SN 71J3772 Engine SN 83Z0704
D6 SN's 4R732sp, 5R2724, 5R4832
D8 SN's 15A1254, 15A2287, 15A2723