The stars before and after the serial number just signify that what's between them is the serial number. c455922 is definitely a 1975 serial number. Yes, a production code starting with a 5 could be 1965 or 1975, but the serial number definitely makes it a 1975 tractor.
The 4m19b on the engine (December 19, 1974 day shift) is the date of assembly of the engine. The major components, engine, transmission, rear axle assembly, were each assembled separately ahead of the final assembly of the tractor itself, usually 1 to 3 months ahead, so a December 19, 1974 assembly date for the engine agrees with a February 2, 1975 assembly date for the tractor itself.
The fact that the model number (C1013C) starts with the letter C indicates that it was made after late 1968 as well, as they used a number (2 for 2000, 3 for 3000, 4 for 4000) from 1965 through late 1968, and switched to letters (B for 2000, C for 3000, D for 4000) in late 1968 and continued using letters through the rest of the production run.
A spin-on oil filter is not indicative of a 1976 or newer engine. They switched from the canister oil filter to the spin on oil filter on November 1, 1969 according to my parts book. My 1973 4000 has a spin on oil filter and the engine is original as far as I can tell. Yours may be a newer engine, but the fact that it has a 1974 date code on it makes me doubt it.
As far as I know, the 3000 diesel engine was 175 ci from the factory for all years (1965-1975). The raised casting numbers on the block and head could tell someone with the right reference books what size you have in there, but I would bet that it's the stock engine.
The thermostart feature was an option, so not all of the diesels will have it. So was the differential lock, which is the one thing that I really wish my 4000 had. It was up to the one doing the ordering from the factory to specify which options it would have, whether it was the dealer ordering from the factory for their showroom or whether it was an individual ordering exactly what they wanted through the dealer.