Steve R, Yes the frame mounts are supposed to be taller on the drivers side than on the passenger side. I've heard this was to clear the steering box.
There is a difference in mounts, both frame and engine, for the 67/68 & the 69. I don't exactly remember why, but if I find it I'll re-post. You can't interchange engine & frame mounts between the 67/68 & the 69. On a 67/68 you can use 69 frame mounts, but then you must use 69 engine mounts and vice-versa.
As stated earlier, they are available from the chevy dealers. When I bought mine they were around $36.00 ea.
Pink68, I'd look closely at your mounts and verify the heights. If they are indeed the same height, that would be cause for concern.
67 Camaro LS6 454/TH400/12bolt 3.73