[YenTy]

You don't need to edit objects to cover it with custom texture. Indeed, you don't even need DL version to cover it with textures includes to SAMP. Anyway, first what I found --> https://sampforum.blast.hk/showthread.php?tid=654971 and then if it's right, it seems that these servers what are you talking about are using logos, themes pictures on invisible, transparent wall. Otherwise, u will need to edit object in blender, not mesh, just texture or logo if it's curved or attached to the rest of it. - last condition requires (for example) tutorial by Kalcor - https://sampforum.blast.hk/showthread.php?tid=643636