Ok, I did a bit of research. The piece of code in question is Title 8, Occupations Code, sec. 1305.160. I have posted it below. It clearly forbids anyone from selling an electric sign unless they are a Master Sign Electrician, or unless they have one employed. The two sections referred to by the OP would exempt those that would sale electric signs, but not perform the work themselves. Looks like this will become acceptable practice on Sept. 1, 2013. The proposed changes (HB 1352, and SB 803) are an addition to a long list of people exempted from the electrical licensing requirements.
Sec. 1305.160. ELECTRICAL SIGN CONTRACTOR. (a) An applicant for a license as an electrical sign contractor must:
(1) be licensed under this chapter as a master sign electrician or employ a person licensed under this chapter as a master sign electrician;
(2) establish proof of financial responsibility in the manner prescribed by the executive director; and
(3) maintain workers' compensation coverage for the contractor's employees through an insurance company authorized to engage in the business of insurance in this state or through self-insurance, or elect not to obtain workers' compensation coverage, as provided by Subchapter A, Chapter 406, Labor Code.
(b) A person who holds a master sign electrician license issued or recognized under this chapter may only be assigned to a single electrical sign contractor, unless the master sign electrician owns more than 50 percent of the electrical sign contracting business.
Here is the text of HB 1352
(24) a person who sells or offers to sell a sign that
requires electrical work or electrical sign work in connection with
the construction or installation of the sign if the person does not
perform that electrical work or electrical sign work.
SECTION 2. This Act takes effect immediately if it receives
a vote of two-thirds of all the members elected to each house, as
provided by Section 39, Article III, Texas Constitution. If this
Act does not receive the vote necessary for immediate effect, this
Act takes effect September 1, 2013.
The text of the Senate bill is identical. Both have been introduced, but no further action has been taken. If they are not brought up for a vote prior to September 1, 2013, then they will take effect by default. The TSA is a powerful lobby, as are the Electricians. They would love to have a locked up monopoly on this business. It is incumbent on us to contact our state legislators to support the passage of these two bills. I will be writing to mine this weekend. Rest assured that the electricians and the big guys will be lobbying to defeat this amendment.