Stopwatch Heuer Ref. 403 220

My name is Renato and I'm from São Paulo, Brazil. I have a Heur REF. 403 220 stopwatch from the 70/71. I want to sell it because I don’t use it and I think a collector would make a better use. However, I sought information on the internet about this model and didn’t find much. Here's what I got:
1/100th of a second, 1 lap in 3 seconds, 0-3 minute counter. Start, stop and reset to zero by the crown. 7 stones, shockproof. Present in Heuer's 1970-71 Catalogue.
The stopwatch was evaluated by the company Antiquorum München by email, in October 2013, with a value from €500 to €700.
I can send more photos if anyone needs. I don't have the original box or accessories. Thanks.

Hi Renato
I have this similar Stopwatch and paid $200AUD
I think $500-700 Euro is very optimistic.

But good luck with your sale.

All the best

It's always a pleasure to see a small snapshot of your incredible collection Anthony, thanks👍

Hello Anthony.
Thanks for your reply. As I said, I'm not a collector and don't understand much about this world. I've found only two ads with the same stopwatch. One from 2011 (£ 144) and the other I couldn't find when it was posted (€ 499). And I found it safer to use the evaluation price. But it's not the final selling price. I accept a value negotiation that is good for both sides.
Awesome collection, by the way.