We can only offer a guess since we don't know the pressure limit on the wheels. A reputable tire dealer should be able to identify the wheel's manufacturer from a name or code stamped on the wheel and look up the specs in a tire and wheel industry reference book. If the wheels are eight lug they are "probably" rated for 80 psi. inflation. If only six lug, they might be rated for less.
Your trailer is not extremely heavy, I'd guess no more than about 2500 - 2600 lbs. on each wheel, so you are probably safe.