More of the better gssf shooters in my area shoot in the opposite order from me - plates, M, 5 to Glock. Their logic is that the plates have low disaster factor as long as you don't leave any standing, which is true. So it functions as warm up for them. For me though, I feel like the level of care in sights and trigger is different enough between the plates and the tombstones that I think the plates are terrible preparation for the stages with tombstones. For me anyway.
I tried shooting plates first exactly once. In addition to being out of whack on the tombstones after the plates, it was also a long and hot day and I was tired by the time I got to 5 to Glock and pretty much sucked. Never going to shoot that order again.
That said, I think I'm in the minority in stage order preference. Most of the better gssf shooters I know do start with the plates and end with 5 to Glock, so it is worth considering.