misterbrownstone, the short answer is...no, there's no way of telling without a pH meter.
Long answer is- sort-of~
Some folks use litmus paper, available at most drugstore, for a general idea. And if you feel so inclined, and have the information, post all the ingredients with quantities, and someone might give you an opinion about the likely pH safety based on similar ingredients in a batch they may have made.
If it's a small batch and it has some kind of acid in it (vinegar, lime/lemon juice, acidic fruit juice), it's pretty safe to just bottle it and keep it in the refer. I wouldn't keep it un-refrigerated without at least SOME kind of idea where the pH is.
There's always the safety net of pressure canning the sauce, if you have the equipment.
have fun and post pics! We luv pics~
salsalady