Wow! Those are $500. Wasn't expecting that.Wilco makes some STC'd adapter plates for them (https://www.wilcoaircraftparts.com/product-p/whelenorioncessna.htm) or you can do some fiberglass work.
Does anyone know if I could replace my lights with the Whelen Orion 650 LEDs?
The Whelens should fit but they are replaced by existing light part number per their documentation. The correct 650 P/N should use the existing wingtip nutplates unless I'm missing something from your post. AeroLEDs are another brand but perhaps get input from your AP prior to purchase as the Aeros may require a different approach than the WHelans.Should I look at a different brand?
As I mentioned there are replacements but the 172 came with a different OEM light assys. So you need to know which light you have to order the correct 650 so it will screw into the same holes. Perhaps give Whelan tech support a call and have them assist with selecting the correct 650 you need?I'm really surprised there isn't a direct replacement seeing how popular the 172 is.
Whelen suggested the $500 fiberglass adapters.
FYI: "suggests" is one thing, ask your AP his input if really needed. Perhaps call AeroLEDs. However, as I recall they are only TSO lights so your APIA will need to determine route to install.Some company has to make LEDs for the 172 that don't require $500 adapters.