10 bolt-differential-28 splines or 30 splines

1990 1/2 ton 2wd 10 bolt 8-1/2" ring gear, can it come 28 and 30 splines or only one or the other. Am I best to pull the axle and count
splines. Need to ship parts south
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.