Yes it is Wratten 89b. Ilford also make the filters available separately: they are gels in a Cokin P size gel holder. Not sure if they are the same material, but the Cokin P007 is also a Wratten 89b filter (but even more expensive so it may be a solid plastic type - IDK)...
So, my problem is that a genuine Kodak gel Wratten 89 filter or the Cokin P007 is the same cost as the SFX pack with 3 rolls of 35mm film..
And I had a braino (typo for the brain... ) and ordered an 87 used from KEH but thought for some reason I was ordering an 89. The 87 won't go to waste with Efke and HIE, but it won't work with SFX....