I am not an idiot savant regarding movements, but I have been watching the prices of Carreras over the last few years, and I would say that you did fine with your purchase. It's a great looking example, and the price seems to be well within the current price range for these Carreras.
As to many of Chuck's comments regarding the Cal 12 movement, I will not seek to defend the movement. It is what it is, and Chuck's observations are all reasonable and unbiased. I can report, however, that I have never had a mechanical problem with a Cal 12 / Cal 14 / Cal 15 movement, once it has been properly serviced.
So let's hope you will enjoy the great looks of your Carrera, that it will provide years of faithful service, and that you will not suffer from the awareness that there may be "better" movements out there. You are collecting "history" and beauty with these old Heuers; the Cal 12 was certainly a great movement in 1969 and a notable piece of chronograph history; yours is housed in a beautiful Carrera . . . enjoy it and share your experiences with the rest of us!!
Jeff