Originally Posted by BandJCarm
Then Possibly I'm misunderstanding, so I'll bow out.
OK, maybe this will help you see where I'm coming from. I went and got some information from the standards I'm quoting.
From FMVSS 571.120 paragraph S5.1.2…the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label
From FMVSS 571.120 paragraph S5.3.1 Tires. The size designation and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle is appropriate for the GAWR.
Notice in the second example where they said "size designation". A size designation includes the prefix. So, with that specific tire description the standard includes the tire design, should it be LT, ST, P or metric.