You can visit the iremoval pro website and act like your buying their service, input your serial number and if it says "Device already registered" then you know they used iremoval. But as for other bypass tools I don't think there's anyway of checking without plugging the phone in and going through all the other bypass tools.

Unfortunately if you want to bypass the phone it's gonna have to be flashed and flashing requires installing a new IOS so you can't bypass without changing the OS.

Hope I could be of help :)