it's more likely to end up damaged from 'stretch' if you inflate cold and it get's left on the beach in the sun than by pumping with the supplied inflator = I was advised when I bought my first..................
if you're going to put on the sailing rig (it's a Tinker Tramp), the manual says to inflate it absolutely as hard as you can, then put it in the water (to cool), then pump up really hard again.
No idea if this applies to all inflatables though.
A knowall kid in the boatyard I used to use inflated his Zodiac hard with a footpump and left it in the sun, despite being warned. The thing exploded like a bomb and the damage was irreparable. There was a two foot tear down one side.
Whilst I do not know the exact pressures etc I would think as long as you can squidge it a bit and use a bit of common sense in hot weather and let a bit of air out you should be ok.
My Avon footpump has a two inch long x 1/2 inch partly transparent cylinder in which is a spring which, I am informed is a 'fuse' to prevent over inflation. It is marked '3.5 PSI'