If only Jim is guilty, then only Bud's statement is true, and the conditions are fulfilled, so this is one solution.

Any other single individual being guilty would result in two true statements.

But the theft may have been a collaboration.

If Jim and Bud were the only two guilty among the three, then only Sam's statement would be true, again fulfilling the condition.

If Jim and Sam were the only two guilty, then only Bud's statement would be true.

Bud and Sam's dual guilt would make two statements true: Jim's and Sam's, and so is not a solution.

If all three participated in the heist, then again only Sam's statement is true, and this is the final solution.

So Jim is guilty along with either or both of the other two.