If I remember correctly I think GHRP-2 you have an active life of like 10 minutes or something , GHRP-6 was significantly longer ,then the addition of CJC-1295 caused an extended release or prolong the release.
There was a bunch of data and testing done on it years ago , but I don't remember where I saw all that data.
But to answer your question I think you could use a GHRP/GHRH to fake a serum test for HGH