Ram Air, which was standard on the Boss and optional on other models, had no decal on the housing or lid other than the '71 Autolite or the '72/ Motorcraft service label on the left front of the housing. There was never any decal or label on the lid. If you are not concerned about originality or preparing a concourse-level vehicle, you should do whatever scratches your itch. I always felt like the air cleaner housing looked like something was missing, with nothing on the lid. The decal I've seen most often used and should fit your lid is the "351 C.I.D. Ram Air" from the '69-70 GT-350 Shelby.
https://www.npdlink.com/product/dec...2Bdecal&top_parent=200001&year=1969&year=1969 As for the blue and white decal in your other post, that decal is for the 72/ standard air cleaner housing lid, and most have a reputation for the arch being off and not fitting at all without some creative trimming!