he's still a cop.
what are you not getting?
find that law and post it then i will believe you.
https://www.txdps.state.tx.us/rsd/vi/misc/faq/viFAQ.htm
Inspection Grace Period
There is a five (5) day grace period for motorists to get their inspection sticker. An inspection certificate expires on the last day of the month that is indicated on the windshield. Therefore, you have until the 5th day of the following month to have your car inspected.
Here is a list of exemptions ...
What's Inspected by Vehicle Type
Items of Inspection for a Exempt Vehicles
15.01 Vehicles Exempt from Inspection
1. Equipment:
a. Road-Building Equipment
b. Farm Machinery
*c. Trailers
*d. Semitrailers
*e. Pole Trailers
*f. Mobile Homes
g. Any Vehicle required to Display a Slow-Moving Vehicle Emblem
*When the actual gross weight or registered gross weight is 4,500 pounds or less.
2. A vehicle with one of the following type Texas license plates:
a. Paper Dealer Demonstration/In-transit/Converter Tag
b. Parade License
c. Former Military Vehicle License
d. In-Transit License
e. Machinery License
f. Disaster License
g. Farm Trailer License
h. Permit License
i. Antique License
j. Charitable Organization Tag
k. All-Terrain Vehicle Validation Sticker
3. A vehicle with one of the following Texas permits:
a. Factory Delivery Permits
b. Prorate Tabs
c. One-Trip Permits
d. Temporary 24-Hour Permits
e. Mobile drilling and servicing equipment used in gas, oil, or crude production having a 72- or 144-Hour Permit
As you can see Dealer DEMONSTATION is exempt, not temp dealer plates for a purchase vehicle.
It's just a fact, you have to get an inspection when you buy a vehicle, technically within 5 days, but some cops with let you slide, I've heard up to a month due to that they are supposedly good until the end of the printed month, and maybe you bought it on the first ...maybe.