Not specific to the Convertible, but another good book every enthusiast should read is another one by Keith Seume "VW Beetle, a comprehensive illustrated history of the world's most popular car." Books-A-Million had them on sale for under $20 a couple of years ago and I ended up getting 4 copies for Christmas that year! (Guess my family thinks I like Volkswagens or something.

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Somewhere on the net a couple of years ago I found a list of month by month production #s. The VIN alone won't tell you much more than the type, year, and body style, but it can tell you (with a list like I mentioned) exactly which month of what year it was produced. Keep in mind that VW's model year runs from August 1st to July 31st . . . so a car built on or after August 1, 1972 will be titled as a 1973 model.
You used to be able to get a "birth certificate" from VW Ag (Germany) that would tell you where it was produced, the exact day it left the assembly line, when and where it was shipped from the factory, and where it was delivered to. I've heard that they no longer provide that service, but I couldn't say for sure that they don't.
Here's what little I can tell you for sure about your car. 71 and later convertibles were all Super Beetles and all their bodies were built by Karmann (the same coachworks company that built the Karmann Ghia bodies . . . but I guess the name kind of gives that one away doesn't it! LOL). Technically did not have "Factory Air." VW never put air conditioning in the Beetles on the assembly line . . . BUT, VW of America did have "Dealer Installed" air conditioning option, which is most likely what you have. There were some other aftermarket units available in the 60's and 70's . . . but most of what you run across will be the dealer installed unit.
When you say the seat belts are 1973 . . . does this mean you're not sure of the year model? '72 and '73 are VERY different animals. '72s had a flat dash and windshield like the Standard Beetles . . . '73 and up had curved windshields and a somewhat more modern looking padded dash. The seat tracks and taillights were also VERY different. If still have a question look at the VIN plate that's rivited to the dash at the bottom of the windshield If the third digit is 2 it's a 72, if it's a 3 it's a '73.
"What's it worth?" That depends on how bad someone want's it and how bad you want to sell it . . . You won't find much in the way of decent, safe, drivable convertibles for less than $5000 anymore, but every now and then someone will run across a great car for less than half that. Those bargains are usually the result of someone who has too many VWs and their only priority is to get rid of something. On the high end, I've seen a few go for over $15,000. Basket cases and rusty verts can still be bought for a decent price, but keep in mind that it might cost as much as $2000 just to have a top professionally restored if the top frame is in poor condition.
As for "How many are out there like her?" None! VWs are like people and snowflakes . . . no two are exactly alike! LOL But, really, there were plenty of Beetle Convertibles made . . . a total of 331,850 built between 1949 and January 10, 1980 when the last one rolled off the assembly line (one exception to the August 1st start date for the model year is that all of the Convertibles built after August 1, 1978 were '79 models, even the handful built in 1980). How many of those are left . . . maybe half? That would probably be a VERY optimistic estimate.
You need to come out to Wally's on the 17th to our club meeting. You can't have too many VW friends when you're restoring a Bug! :cool:
Edited By Zen on 1046923355