When used correctly they were pretty good back then,The problems started when the primers started going on way to thick to try to cover all the rushed or poor body work, then when that wasn't enough out came the glazing putty and start slathering that on there,I've seen that a 1/4" thick....but when used correctly lacquer primer worked fine so did the glazing putty ,nitro stain being the most popular. Lets face it ,if the scratches are any rougher than 180 you'll have problems later especially these days you cant get any GOOD lacquer its all wash thinner..and if you had to do any filling to get your body work straight, your screwedYour body work HAD to be right and GOOD bodymen were in great demand. Everything is a lot easier today..and Good bodymen that can get the panel right without fill primers are few and far between...we sanded and blocked bondo up to 320 before priming back then now its not un common for any one to prime after 80...Thats something you could NEVER do back then