The Richdel/Lawn Genie are exactly the same valve other than the color.
The Richdel was sold to commercial distributors and they were are gray in color. The lawn Genie products were sold to hardware stores and were green in color. There is no diffrence between the valves at all.
So don't be afraid to pick up Lawn Genie parts to fix that richdel valve.
they will work just fine.
Hope this helps.