bought mine (77) a couple weeks ago on ebay and got it delivered to Houston and a replacement NR rear derailleur installed for less, so I think it's a bit high. Also, I'm not seeing any of the original decals or accent stripes Has it been repainted?
In a discussion about 70s Motobecanes not too long ago, one of the experienced folks commented that the Grand Records sometimes came in with Nervar cranks, so it may be original to the bike, though not matching any catalog.