[GVS]

Thank you for sharing these pictures. Arntz Cobras used an MGB front suspension and Jaguar rear suspension, which appear to be present here. Arntz used MG exposed trunk hinges, also present. The door beams and interior handles also look like an Arntz. The dash is not from an Arntz.

I am not an expert, but from these pictures it appears to be an Arntz Type 2 (roughly produced 1978-1980), based off the door beams (which I do not believe were in the Type 1) and the lack of weather-stripping / drop rails around the hood and a notch for the distributor (features which appeared on the Type 3). Most of these vehicles were sold as kits and assembled by the buyer. The VIN you provided "7R03T177836" is from a 1967 Mustang convertible and decodes as:

7 = 1967 model year
R = San Jose, California assembly
03 = Mustang convertible
T = 200cid I6 engine
177836 = serial number

So someone used a Mustang VIN to register this vehicle.

It looks like a well built vehicle. If it were a Butler, it would have a chassis number on the left front frame rail. I do not believe Butler would have registered it using a Mustang VIN. All of the Butler vehicles (104 in total) used an Arntz Type 3 body.

As Motorhead stated, fuel cell foam has a 5 year service life. Enjoy your Cobra!