I don't know who the vendor is, but S&P Communication 'stages' systems on their old IMTS frequency pairs.
Some do this to test the system before going live and on the actual FCC assigned frequencies, avoiding interference issues with the legacy systems-provided they are staying on the same frequencies.
(Not to sound condescending) For you younger folks, IMTS was the first mobile-based telephones that ran on 152.xxx and 158.xxx and were operated predominantly by Southwestern Bell in the 70's. They were true boat anchors, the trunk mounted transmitters were the size of 3/4 of a filing cabinet drawer, weighed 50lbs and had a huge "control head" with 16 channel selectivity and a rotary dial. I digress.
You may find licenses to Nathan Sherman (owner of S&P) or another vendor in that area, but your search for licenses will need to go outside the realm of the public safety user base.
Balcones Heights PD continues to operate on a 152.xxx frequency of Sherman's and has for several years.
~S~