The grease seal your looking for;
ID 1.719
OD 2.565
Item # 58846 on etrailer.com
Dexter 3500lb axle with 10" drum brakes
And some other cross reference numbers for the same seal. Odds are a local auto parts store will have them. If you want to stay with Timken, NAPA usually has them or can have them the next morning. Timken is a premium brand and is more expensive. Amazon also has Timken if you are a prime member that is usually the least expensive way to get Timken seals. I just ordered a set of 4 for my Forest River (yes, I sold my Hilo some years back but being an original member of the group I still hang around here). The seal is a double lip seal and should have a spring tension backer on the inner side:
LCI# 122087
Timken #473336
Dexter 010-019-00
Transcom #171255TF
National 473336
NOK AD2548EO
Timken 473336 seals on Amazon (note the 4 I received this week were made in Taiwan, but they are genuine Timken sold and shipped by Amazon and not a 3rd party vendor. Others have seen USA and India made seals, but the quality is still Timken):
https://www.amazon.com/gp/product/B001544U88
Some other numbers from my notes for my Hilo show the bearings and races. Timken bearings and races should be all USA made and have a hologram on the back of the box along with a serial number. You may want to double check the dimensions in case your trailer has a different set of axles (mine were 3500lb):
Outer bearing cone L44649, LCI# 122089 Timken set #4 (race & bearing set)
Outer bearing cup L44610, LCI# 125102
Inner bearing cone L68149, LCI# 122092 Timken set #17 (race & bearing set)
Inner bearing cup 68111, LCI# 124296
Hope this helps someone....