Definitely a most interesting piece -- first one I've seen.
As the issue is with the coin's planchet and not the result of a coinage die defect, your Texas could very well be unique -- possibly a single bad planchet among the 10,000 used by each mint (P, D, S) to strike the Texas coins in 1935. Definitely a conversation piece for one's collection!
I don't think there is a real need to have it resubmitted (and pay the additional fee) to have the 'Cracked Planchet' added to the holder's label. If it's visible to the naked eye, it will be easy to explain/point out to a potential buyer if you decide to sell it. I say this because there isn't a huge collector base "fighting" over the available 'cracked planchet' coins -- many (most?) sell for only a minor premium over the same coin without such a planchet defect.
Collecting history one coin or medal at a time! (c) commems. All rights reserved.