*037796* looks like a serial number, but there should be a letter before the first *, either an A, B or C, which would tell us what factory it was assembled at. Given that the number is so low, it is probably a 1965 or 1966 tractor, but the C serial numbers (US plant) started with 100000 with the new models in 1965, including the 3000, so that number, if it is correct, would probably be an A (Antwerp Belgium) or B (Basildon UK) tractor.
C118 is not a correct number for a model number, production code or serial number, although it could be the beginning of a serial number, in which case it would be a 1965 serial number.
The third number is probably up a little from the 2 that you found, on the rougher casting, not on the part that has been ground smooth, so it's usually harder to spot.
Another possibility is that they sometimes stamped some of the numbers on the same flat spot on the left side at the European assembly plants, so you could look over there to see if you can find any numbers.
If you have cleaned all of the dirt and paint off and those are truly the only 2 numbers there, then the transmission itself could be a replacement that the dealer didn't stamp correctly when it was replaced.
If it is a 1965 or 1966 3000, it should have the louvers in the sides of the hood and the rear axle housings (trumpets) should be square, but the draft spring for the 3 point lift should be exposed, as they didn't enclose the spring on the 3000 until April of 1967, and they switched from the louvered hoods to the smooth hoods in 1968, and the 2000 rear axles were round until sometime in the early '70's.
Also, you should be able to find a date code on the right side of the engine, on the smooth flat rail in the casting just above the oil pan near the front. That should tell you when the engine was assembled, and if it's the original engine then the tractor was most likely assembled 1 to 3 months after that.
Post some pictures of the left and right sides of the whole tractor, and closer shots of the front and rear that show some details of the grill, the axles and the 3 point lift and we should be able to narrow it down to a possible subset of models that it might be.