JK, Yes they are on both sides. Pretty simple really; the black plastic on the TBRs are Delrin which is a joy to machine on either a table saw or router table. I just figured out about where I wanted to mount the HWY Pegs. The pegs are cheap'ies since it was really going to be a test of the concept. Got them on Amazon.
https://www.amazon.com/gp/product/B00W67TI9Y/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1, $22.
In fact they worked out pretty good. See the photos. It was a bit of a toss up with regard to how far forward I could mount the pegs and still reach them comfortably. This position worked best for me, 5'-9", 33" inseam. Essentially, I "dado'd" out a channel on the bottom of the Delrin block to clear the peg mounting assembly. Not my best work, but it fits. If you do this, take less material off to make it so the peg can fold up when not in use.
Bought longer through bolts to mate the pegs to the square mounting bar strap that wraps the TBR bar; enough to make sure that the square peg mounting had a good bite on the U strap and washers so the assembly would not rotate on the TBR round bar. M10 X 1.25MM X 70MM Grade 8, if memory serves, to reach the peg shaft after I put spacers in line like thick washers to make the gripping cones of the peg actually do their job.
I ended up drilling and tapping some set screws I had lying around on each peg to angle it up at the pivot point, two in each peg. This is because the angle that the pegs end up at when mounted on the TBRs cants them forward such that your feet want to slip off. The set screws allow me to control the angle for each peg to fit the desired resting angle of my foot. Put on some CF stuff I had to replaced the plastic inserts that pass as peg pads.
I was going to take them off unless taking a longer ride, but they don't bother me and I forget they are there. To me it is the sign of a good accessory.
Let me know if you need any other info, be glad to help you figure it out if/when you get the TBRs!
Cheers!
Gilbysan