Dave, I'm sure you've figured out by now that the bayonet lug is part of the front sight group. I suggest you don't mess with it if you're concerned about the value of your rifle. I think you've already come to that conclusion.
Having said that, all Russian SKS bayonets are not created equal. This website will show you the difference in Russian blade bayonet lugs. http://www.yooperj.com/ Click on SKS on the left side of the page; then scroll down to "SKS page 4 more info on bayonet lugs".
Having said that, all Russian SKS bayonets are not created equal. This website will show you the difference in Russian blade bayonet lugs. http://www.yooperj.com/ Click on SKS on the left side of the page; then scroll down to "SKS page 4 more info on bayonet lugs".