This particular 914-6 oil filler neck reproduction is not "GT", but it does have the large opening of a GT oil filler. The reproduction oil filler neck in these photos is clearly missing the provision tube that allows the very important "Preschona Oil Pressure Relief Valve" component to be connected and becoming the crucial piece in the racing lubrication system of the 914-6 GT. See here https://pbase.com/9146gt/image/22561541

See here https://pbase.com/image/167279361 then the OEM 914-6 GT version https://pbase.com/9146gt/image/90361731. I'm not trying to be critical, just clarifying the correct information.