The M1D is much easier to clone than the M1C. The reason is because the M1C scope mount requires the receiver to be drilled and tapped, this in turn requires the receiver to be heat trated again. Griffin and Howe still sells the original type mount and base and they can install it for you for around $600. The M1D uses a block for the barrel that can be installed by any gunsmith on any M1 Garand barrel. The original scopes for the M1C were the M81/82 Lyman Alaskan series and they will run about $1500-$2200. Some C's had the M84's as replacement scopes, these are about half of an M82 cost. The flash hiders (cone type) are very expensive and hard to find loose. There are reproductions out there for these. The T37 prong type was used on later M1D's and can be seen on the rifles used in Vietnam. Many CMP rifles that have gone through the arsenal rebuilds will have this type. Both M1C and M1D used a leather cheek piece, these are also costly if original, repros work good and are pretty cheap. Most of the M1D's were built in the latter part of the Korean War, M1C's were built late in 1945 and the early stages of Korea. It may be better to find an M1D that came from the CMP or one that has already been put together by someone else, may be cheaper than all of the parts needed. Technically all M1D's are put together rifles and they are very hard to prove original unless there is DCM or CMP paperwork.
I know of a real one (M1D) for sale on consignment at a local dealer by me. If you want the info contact me, and I'll foward it to you. Oh yeah the guy wants $4,000 for it. It comes with full documentation on the piece.