It is a no no.
You should clean the threads, use Aeroshell 33ms on the castle nut (prevent galling), torque to 38-42 ft pounds and stake in 1-3 locations pending your castle nut style and where the torque ends up placing the staking notches. Generally you can get 2 much of the time, up to 3 if...
"Yes" you can grind/dremel them off, however, milling the weld off and dropping the pin is the most ideal way to save the MD and lowest risk of damaging your barrel and MD. I have milled 2 off and the treads on the bbl and MD were both fine afterwards.
I went the Aero M5 route a few years ago, was not very pleased with their CS about accuracy issues and the fact their BA bbl's were (no idea if still) morbidly over gassed. I sold it and got an SR-25 and a Seekins SP10.
For what it is worth, the Seekins can be found for like $2400 and less...
These are $1280 dealer cost from RSR, $430 discount from dealer cost to have under 300 rounds fired. No one wants a deal? These are $1400+ at most stores.
This item has been relisted. The new listing can be found at https://www.theoutdoorstrader.com/threads/fs-ruger-precision-rifle-rpr-6-5cm-850-under-300-rounds-gen2.3274566/.
Item Name: Item Gone: FS Ruger Precision Rifle RPR 6.5cm - $850 - under 300 rounds - Gen2...
Location: Euharlee
Zip Code: 30145
Item is for: Sale Only
Sale Price: 850
Caliber: 6_5_cm
Willing to Ship: No
Bill of Sale Required?: No
Item Description: Selling my RPR in 6.5cm. I purchased it...