The general contract law principle is: if both parties have signed a contract, it is legally valid. Whether copies are possessed by only one party or both is inconsequential.
Exceptions are if the contract contains language mandating that both parties should receive a copy, or if there are specific laws regulating the form of such contracts.
In other words, your signature is on it, but you've never seen their signature on it.
(Company State = Texas... and I don't reside in Texas)