Replacing old rubber on leaky portlights

Hello, On my Freedom 35 CK the rubber in the plastic portlights are tired and have lost their elasticity. as a result they don’t seal properly (a sliver of light visible despite how tight they are tightened) and allow some dripping. Can these rubber seals be replaced? The portlights aren’t the “U channel” type instead they have contact on 2 sides and there may be a lip they slide under. before I start making things worse I wanted to see if there was any advice from the mass of knowledge here. a quick Youtube search only provided how to on u channel type portlights.

Thank you in advance for your insight.