The biggest factor affecting oak flavor is how, where, and how long the oak was aged. Big deal coopers in America will ship American oak to France to age because of the microflora in the woods there. They'll age them for like 3+ years before shipping them back and making barrels out of them.
But that's for distillers who might put $1m worth of product in a single big barrel, so they really want to be sure they have the best possible barrel.
Without knowing more about those barrels, it's hard to say. But since they're made for tequila and they're inexpensive, I would bet they weren't aged for a long time.
That said, they're cheap enough it might be fun to try out, but I wouldn't expect anything amazing. If you want something really good, I'd save up for a used whiskey barrel.
To paraphrase Dr. England - "Off-flavors smooth with time. So do mountains. Brew it right from the start!"
My blogsite: http://nateobrew.blogspot.com/