Finally got around to working on swapping out the 601 tank to an original 801 tank on my 861 and had a couple questions. When I pulled the 601 tank to dry fit the new one before painting it, there was a square piece of leather under the front mounting rail. Is that supposed to be there or did someone put it in for vibration, noise, clearance or whatever? Reason I ask is, you can see in the picture, if I leave it in with the original 801 tank, I'll have plenty of clearance for the heat shield. If I remove it and mount the tank right to the steel, I'll either have to get a smaller muffler or just use a little muscle to move the muffler down 3/16" or so. What do you think? Also, I need to get a couple new rail mounting bolts. Are those just 7/16" fine thread bolts? Need 'em 3/4" instead of the 1-1/2" that were used on the 601 tank. Smaller rails on the 801 17 gallon tank.