Hi Cesar,
You kindly emailed me, so you have done your homework.
I am giving you my best opinion, but others may disagree. The Sebring has never been as popular as a Monte Carlo,
maybe because of the marketing and 'history' of the Monte or because of the Monte's moving window. This makes it more popular for the rallying navigator, but the Sebring may be more popular for lap timing done from the race pit wall. I do not know about the history in the US, where it may be more popular. I have a chrome one engraved KOLB, who I believe was an American Race Driver.
Regarding value. For the right buyer, wanting to match this with a Mastertime, a NOS plastic Monte may be worth around $600. But I may be wrong.
Best of Luck
David