Actually Supro & McKinney are just brand names, Valco was the manufacturer of them both along with National/Oahu& about 3 or 4 morelap steel brands all made fromValco,even the amps.the student models are easy to spot because they're super short(meant for kids-teens)and the pro models are usually square shaped.I haven't seen a McKinney student model before seeing your video,I've only seen their deluxe models,really nice mother of pearl covered stuff with great sounding pickups!!!
Ya thought you may have built it just checking I got a sweet hook up with a cigar shop for boxes liked the looks of it checking to see if it was manufactured to get my hands on one. I havnt tried building a box yet may have too want to try a reso and Ive only found them in 7" may fit in a JFR box my new fave. Im gonna go measure now thanx for the inspiration