In Back to the Future 3 (1990), the year in this scene is 1955 and Marty says: Clint Eastwood would've never wear anything like this. By his side there is a poster of Revenge of the Creature (1955) which marks the film debut of Clint Eastwood.

Image from preview.redd.it and submitted by SilDaz
image showing In Back to the Future 3 (1990), the year in this scene is 1955 and Marty says: Clint Eastwood would've never wear anything like this. By his side there is a poster of Revenge of the Creature (1955) which marks the film debut of Clint Eastwood.

SilDaz on August 8th, 2020 at 04:09 UTC »

You can also see the poster of Tarantula (1955) in which Eastwood also appears.

Edit: I took this detail from the Cinsemassacre video where they review the History of horror films

Link

Spackleberry on August 8th, 2020 at 06:17 UTC »

Marty gestures at the posters when he tells Doc, “That’s right, you haven’t heard of him yet,”

Treebeard431 on August 8th, 2020 at 06:17 UTC »

'Would never wear' or 'would've never worn'