Windows packages are being wrongly detected as as an msi installer

I have been configuring windows installers but some installers write their registry key as a guid and salt assumes all installed entries starting with a '{' are msi installers and it will then filter ones that want to write a guid and are not msi installers. I changed it to look at the key that checks holds whether or not it is an msi installer.

An installer that had this issue was the ruby 1.8.7 windows installer