Transferring skins over to another engine shouldn't prove to be an issue, models are usually universal.
Some work will have to be done though I extremely doubt they're going to do this as this could potentially kill off the playerbase that paid previously which would technically lose all their content for no real reason.
it is possible first you put the half life 2 into blender here is the video showing how
heres another tutriesl
Blender - How to import Source 2 Map into Blender - Steam Lists
Great news, I could finally have a good look at the maps. Already own UE software.
Just a small sidenote on this topic. Respawn is currently using unreal engine 4 (not 5) on the upcoming release of the Jedi Fallen order sequel. The first game was really good by the way.
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