You are NOT reading through ANY of the descriptions!
I have edited and cleaned up the Amazon listing description below.
The Kuryakyn 8905 is a later Satin Black version which fits TRIUMPH model peg mounts but some may be for FRONT and some may be for BACK. These 8905 are FRONT ONLY for R3s as detailed in the online description.
There are now also Kuryakyn Adaptors which have an 'adaptor for the adaptor' to allow use either Front or Rear!!





Compatible with Triumph models
Using front OEM peg mounts only:
All '04-'18 Rocket III; '10-'18 Thunderbird Storm
Using Rear OEM Peg Mounts Only:
'96-'01 Bonneville SE, '02-'18 Bonneville T100 Front or Rear OEM Peg Mounts: '95-'03
Thunderbird, '98-'03 Thunderbird Sport, '96-'01 Adventurer, '99-'01 Legend, '02-'10 Bonneville America, '03-'18 Speedmaster
Kuryakyn 8905 Splined Male Mount Peg Adapters for Front/Rear Footpegs and Floorboards: 1995-2018 Triumph Motorcycles, Satin Black, 1 Pair
Compatible with Triumph models
Using front OEM peg mounts only:
All '04-'18 Rocket III; '10-'18 Thunderbird Storm
Using Rear OEM Peg Mounts Only:
'96-'01 Bonneville SE, '02-'18 Bonneville T100 Front or Rear OEM Peg Mounts: '95-'03 Thunderbird, '98-'03 Thunderbird Sport, '96-'01 Adventurer, '99-'01 Legend, '02-'10 Bonneville America, '03-'18 Speedmaster
Some of the code number differences are solely due to color such as Chrome, Black, Gunmetal which is why over time more options have become available. I believe some may also be availab;le extended length mnow. Over time a number of peg mount designs have become standardized across brands and different models allowing a wider choice of alternatives of both pegs/boards and adaptors.
I often buy Chinese eBay pegs and boards listed for other Metric brands and models because you can check the Kuryakyn adaptor fitments to work out which Metric Jap and Euro bikes have the same mounts as our R3s, even if they are in reverse use. i.e. our back fits their front and or vice versa.
You can mount floor boards or pegs on R3 Stds/Classics and Roadster front or rear or both. R3 Tourings can ONLY git factory floor boards and do NOT require any adaptors as no ready to go peg option.
Theo R3 Stds/Classics and Roadster Splined adaptors differ for front or rear as do the tapered peg adaptors to allow use of Kutyakyn or Harley pegs etc.[/QUOTE
Sorry, you already addressed this....front only
"but the 8905 lists as front and rear compatible, I think it said it includes spacers, which i think would be used for front board mounting"