Lug nuts

So...I just recently realized, after reading the threads here, that I have the wrong kind of lug nuts on my wheels (for this discussion my truck mine as well be factory stock). I'd like some suggestions please and was wondering if any lasting damage has been done to my truck? I have the steel work rims.

06, 4wd, 5spd, 6 lug pattern.

 

I'm not a log nut expert, but will ask what' wrong about them. Might help if you'd explain what's going on.

 

Well...maybe I have the correct ones after all.....chasing down the infamous steering wheel shimmy vibration.....I still need to do a balance and rotation and alignment....but would like to chase down any bad parts before that....checked the u-joints today and I think they are all ok....I may end up replacing them all though due to the fact that I have neglected to grease them for the past 90k or so (yeah I know I'm asking for the needles to be dust but they seem tight?). Anyway I have acorn lug nuts but I guess this is OK with the steel wheels?

 

Yes, that is what you should have.