I had one just like it years ago. Be careful to pin the door back into it's retainer or it'll bust on you. Mine did and all the nice little appointments on the door for holding threads etc and the hinge were all damaged.
Mine didn't have that nice rear flap - ideal for FMQ!
I finished up gifting it to a friend. Hang on, that may sound familiar.
Is your's in good order? Nevertheless a lucky score! Well done!