Beak extender is OE but not at all expensive.
I bought some handguard extenders a few years ago for about £10 from someone selling them on this forum and they worked very well but after 3-4 years they had gone brittle and started to crack. Before throwing them away I used them as a template to cut some new ones out of an old (black) plastic oil-container, fitted them and they are perfect while costing me nothing but a few minutes work.
I challenge anyone to tell me they were not an expensive aftermarket accessory.