What is the opinion of Reddit about the
A Full Set Keycaps PBT 87 Key Caps Replacement White for Logitech G813 G913 G815 G915 TKL Switches Mechanical Keyboard (White)?

A total of 1 review of this product on Reddit.

If you are refering to keycaps in the link below, I highly doubt they are PBT judging from the photo with the stem.