I would call/e mail DSE and ask. I'm going off of what's in my 2nd gen which I believe has the engine placed farther to the rear. My concern with the 1st gen is the engine is located farther to front of the car and the LS7 oil pan has 2 drain plugs, one of which is in the front of the sump area. I would plan on tunnel mods to optimize the driveline angle regardless of the mounts used, it's really not that big of a deal to mod the tunnel.
Here's a pic my old engine with the stock pan in my 2nd gen.
