AFR gauges

Have the opportunity to use an AFR reader that you attach to end of tailpipe. Belongs to a buddy in Texarkana & all I have to do is show up & buy'em a burger.
My question is, are they accurate or put me in the "ballpark" on AFR?

Sample should be taken close to tje exhaust port as possible .

I can go as far as the collector. I might have a curveball thrown @ me. I examined the baffle & I can't see shoving a sniffer past the baffle & into collector area. I spy a small opening @ end of convergence, but it's small & I don't know the dia of sniffer tube.
Could be a problem....

Can one take the muffler off and take the sample from an open pipe?

Nope it will throw the afr off it would show lean do to very high exhaust flow. What i did on my thunder header was take a long drill bit and right in the center of baffle made a very small 3/8 hole .and i ran the 3/8copper tube into the pipe . Worked for me and did not effect the sound or power.

Lugnut, Please take this in good humor. To be really scientific to the extreme you could check the front and rear cylinder each and drive yourself crazy chasing your tune-up. Ride it like you want to, check the plugs for peace of mind and listen for any death rattle. In other words ,enjoy the ride.

Lugnut, it's your rude brother so do whatever you please with it and post it too so we can actually have conversations motorcycle related.