What really matters is not only can you make it fit, but whether power, ground and signal contacts line up as they should. So, you need to know what those are on the socket and how they are on the DIMM.
If you have an ECC modules that has a multiple of 9 memory chips on it AND you can cut away some of the tab so only signals from the ninth chips are disregarded then it could work. If you would toss the as is DIMMS if they don't work, then it could be worth a shot.
Another factor besides fit is whether the DIMM is registered or not. In this case registered means has a register or buffer for the data. Some motherboards need registered DIMMs, yours does not. If your DIMMs are registered, you may have an incompatibility. I have had a mobo that did not need registered DIMMs have sporadic memory glitches with a registered DIMM.