In Monterey next week, RM Sotheby’s will auction off a rare Ferrari 250 GTO – arguably the Holy Grail among the world’s top classic car collectors and a veritable secret pass into an elite club. But it won’t be the only one of its era on offer during the festivities, and it may not even be the most prominent.

The same auction house is also offering this 1963 Ferrari 275 P through its newly launched private-sales department. It hasn’t publicized the asking price, and it may not garner the same $50-million estimate that RM’s placed on the GTO. But we’d argue that it should – for one simple fact: namely, that this is the only Ferrari known to have won the 24 Hours of Le Mans not once, but twice.

Chassis number 0816 is recorded as having won Le Mans in 1964, which remains the last time that Ferrari ever took overall victory in the legendary race (though a 250 LM entered independently by NART won the following year). But further research shows that it actually had won the race the year before, too.

Why the confusion, you wonder? Because Maranello had sort of fudged the records in period. The team was originally supposed to field another of the same at the race in 1963. But apparently the one registered – number 0814 – had crashed at the Nürburgring a month prior, and was still being repaired when it was supposed to venture to western France. So rather than resubmit its paperwork, Ferrari simply sent 0816 in its place. But it was actually the example offered here that took the checkered flag in ’63, and again in ’64 (not to mention the 12 Hours of Sebring that it won in ’64).

The historical revelation makes this 275 P even more noteworthy now than when Artcurial had it consigned for its Retromobile sale this past February (when it apparently did not sell). Further adding to its lore is the pride of place that it took for 48 years in Pierre Bardinon’s prestigious Mas du Clos collection, which was famously described by Enzo Ferrari as the reason he didn’t need a museum at the factory in Maranello (and which has since been slowly liquidated).

“This 275 P is without question the most historically important sports racing Ferrari campaigned by the Works team and we are tremendously honored to offer the car for private sale on behalf of the Bardinon family,” said RM’s European specialist Augustin Sabatié-Garat. “As the pinnacle of the Scuderia works cars, the 275 P offers the perfect juxtaposition to the 250 GTO on offer in our Monterey auction—which represents the pinnacle of Ferrari’s privateer GT cars. The other three 1963 Scuderia cars remain in long-held, significant private collections, and this is certainly the most important of the four built, making RM Sotheby’s presentation of the 275 P truly a once-in-a-generation opportunity.”

So just how much is it worth, exactly? We may never find out, being offered as it is by private sale (and not by public auction). But consider that RM Sotheby’s sold a similar 250 LM in Monterey three years ago for $18 million, and another in New York in 2013 for $15 million – and though technically related, neither of those hold the kind of history that this 275 P does. So we’d be surprised if it didn’t end up selling for a much higher price.

Photos by Remi Dargegen, archive images from the Klemantaski Collection, courtesy of RM Sotheby’s