Fox 36 27.5´´ travel adjusting

[Roadrocket]

I´ve got the 2018, Factory 36, FLOAT, 170mm, HSC/LSC, FIT fork and I ´d like to adjust travel to 160mm. Fox manual says I need the air shaft 820-02-452-KIT(fox part number), but I cannot find it anywhere.
Will the newer version airshaft https://www.silverfish-uk.com/Products/ ... 1-287-Bore fit my fork too? Dealer said the older part is discontinued.

Thanks