Yes you should appoint proper parts inside 3dmotion for each mount you have in game...
here is an example of part for 1 mount - ShadowKnight skills covering:
Part taken from official...
000097001480780=c3/0001/480/780.C3
000097001480781=c3/0001/480/781.C3
000097001480782=c3/0001/480/782.C3
000097001480783=c3/0001/480/783.C3
000097001480784=c3/0001/480/784.C3
000097001480785=c3/0001/480/785.C3
000097001480786=c3/0001/480/786.C3
000097001480787=c3/0001/480/787.C3
000097001480788=c3/0001/480/788.C3
000097001480789=c3/0001/480/789.C3
000097002480780=c3/0002/480/780.C3
000097002480781=c3/0002/480/781.C3
000097002480782=c3/0002/480/782.C3
000097002480783=c3/0002/480/783.C3
000097002480784=c3/0002/480/784.C3
000097002480785=c3/0002/480/785.C3
000097002480786=c3/0002/480/786.C3
000097002480787=c3/0002/480/787.C3
000097002480788=c3/0002/480/788.C3
000097002480789=c3/0002/480/789.C3
000097001480754=c3/0001/480/754.C3
000097001480768=c3/0001/480/769.C3
000097001480769=c3/0001/480/769.C3
000097001480770=c3/0001/480/770.C3
000097001480771=c3/0001/480/771.C3
000097001480772=c3/0001/480/772.C3
000097001480773=c3/0001/480/773.C3
000097001480774=c3/0001/480/774.C3
000097001480775=c3/0001/480/775.C3
000097001480776=c3/0001/480/776.C3
000097001480777=c3/0001/480/777.C3
000097001480778=c3/0001/480/778.C3
000097002480754=c3/0002/480/754.C3
000097002480768=c3/0002/480/768.C3
000097002480769=c3/0002/480/769.C3
000097002480770=c3/0002/480/770.C3
000097002480771=c3/0002/480/771.C3
000097002480772=c3/0002/480/772.C3
000097002480773=c3/0002/480/773.C3
000097002480774=c3/0002/480/774.C3
000097002480775=c3/0002/480/775.C3
000097002480776=c3/0002/480/776.C3
000097002480777=c3/0002/480/777.C3
000097002480778=c3/0002/480/778.C3
000097001480946=c3/0001/480/946.C3
000097001480947=c3/0001/480/947.C3
000097001480948=c3/0001/480/948.C3
000097001480949=c3/0001/480/949.C3
000097001480950=c3/0001/480/950.C3
000097002480946=c3/0002/480/946.C3
000097002480947=c3/0002/480/947.C3
000097002480948=c3/0002/480/948.C3
000097002480949=c3/0002/480/949.C3
000097002480950=c3/0002/480/950.C3
000097001480746=c3/0001/480/746.C3
000097001480753=c3/0001/480/753.C3
000097001480759=c3/0001/480/759.C3
000097001480760=c3/0001/480/760.C3
000097001480761=c3/0001/480/761.C3
000097001480762=c3/0001/480/762.C3
000097001480763=c3/0001/480/763.C3
000097001480764=c3/0001/480/764.C3
000097001480765=c3/0001/480/765.C3
000097001480766=c3/0001/480/766.C3
000097001480767=c3/0001/480/767.C3
000097001480779=c3/0001/480/779.C3
000097002480746=c3/0002/480/746.C3
000097002480753=c3/0002/480/753.C3
000097002480759=c3/0002/480/759.C3
000097002480760=c3/0002/480/760.C3
000097002480761=c3/0002/480/761.C3
000097002480762=c3/0002/480/762.C3
000097002480763=c3/0002/480/763.C3
000097002480764=c3/0002/480/764.C3
000097002480765=c3/0002/480/765.C3
000097002480766=c3/0002/480/766.C3
000097002480767=c3/0002/480/767.C3
000097002480779=c3/0002/480/779.C3
In attachmet I am putting as well example of 3dmotion that I made for DO - it covers all weapons: 410/420/440/450/453/480/483/490 (453 and 483 - are typically for my needs addiotnal

)...
But you checking it how its built you should see more clearly whats the structure of this

So generally you need to build own pattern and prepare this for all single mount (you can make already for all 100 mounts...)
Hope this will help you little out there
cheers