Nice finds!
Last Chance Garage seems like something I've seen in the "aftermarket" like in an antique shop. Willys service one looks authentic. Globe one looks like a repro too, the lettering just looks "off". It's hard to describe, but lettering and typeface/font used on something like this, if it's original artwork, has a different appearance to it. Lettering used to be laid out and drawn/painted by hand, and I've noticed that many times when a sign is reproduced, to get around a copyright, something will be changed. The styles end up not "meshing" or being cohesive with the overall design and pattern....
Many decades ago, my parents had a big vintage automotive sign collection. I grew up looking at these, and looking at other vintage signs, logos and ads, and I studied them. Lettering has been a hobby/interest of mine for most of my life, and I used to make, draw and lay out all the signs and flyers for our auto parts store. Also have drawn up and made several posters for friends with bands.... One of the signs we had, was a huge GMC parts and service sign that would have hung from the front of a dealer shop, in the 1940s-50s. The basic design is available in a smaller reproduction (think about the tin signs you see at Hobby Lobby or an antique shop, or in mass quantities from a swap meet vendor) but they changed the typefaces and it doesn't look "right". The letter styles are more modern than the original GMC logos and artwork/layout.