According to Locke Art Glass by Jane T. and Joseph H. Locke,
80% of the pieces are signed within the etch with either 'Locke Art' or 'Jo Locke'.
Locke made elaborately detailed designs of people, fish, flowers, etc. that in most cases would be easy to recognize, even without the signature.
Locke didn't make glass, he bought it to decorate. Family members remember that he preferred high quality glass from Belguim and Austria, but he did buy blanks from US companies to use when he couldn't get his European supply. The US companies also gave him samples to try in hopes of getting larger orders. Locke claimed that each kind of glass called for its own set of resist and acid etching conditions.
Another problem (if you could call it that): Estimates are that 75% of the etchings were done FREEHAND! Joseph Locke would draw the design by hand and workers would apply the resist and finish the process. Therefore each etch may be slightly different, i.e., the leaves up or down, extra petals on the rose, etc.