Sunflowerzz

I purchased a lovely Montgomery Wards Signature machine awhile ago and unfortunately she didn't come with much. However she is well marked. Here they are:

HAPPY is all over the bottom
J-A10 is stamped in yellow
Motor is URR 1-20
Has RSMCO
Model # R100
Model # URR-82
And 35X188 B

I know a few of the marks meanings but not all of them. What is HAPPY? What is 35X188B, J-A10 and RSMCO?

Will a Singer manual 15-91 work? Is that the machine she was cloned from?
Thank you for any help. I want to get her cleaned up and running but since I am so new the manuals really help me...a lot!