Garands are such a hot collectible these days and there is so much to know that it would be difficult to even give a range.
Because the rarer variants M1D, MC1, Type 1 NM are getting up there in price, there are folks putting left over part together to assemble their own. Of course these are no more valuable than the sum of the parts.
Where the value comes into these is if there is documentation that it was actually recorded as an M1D in the CMP's or other recognized databases.
If you are fairly certain the serial number will check out, you might consider sending the rifle in to Scott Duff (
http://www.scott-duff.com/to have him do an appraisal.
What you describe sounds like a nice rifle with a nice story behind it, but I don't know any that would pay the dollar verified M1D's are getting without documentation. The 1941 date might be the date the receiver was produced, but M1D's weren't produced until a few years later. Probably pulled back into the arsenal and rebuilt as a D.
Good luck.
