Shifter stop

[72K5NTX]

So since I bought my 72 K5 the shifter has been a bit funky. Really loose and it does not need to be pulled back to shift into gear (automatic trans) like in my other truck (newer). so I believe the problem is at this plate on the column that resricts the shift lever from moving when in gear unless you pull back on the handle. I have no idea what its called and the pic is not that great but any info would be appreciated. If it could be replaced, what would it be called?