Yup. Used my Indian number.
Just a heads up - on the signup form, when they ask for contact information, I choose "Outside Canada" as my country. The lady who called me didn't let me book an appointment because apparently, I filled the form wrong.
If you fill out the form, choose Canada and choose the name of the province you will be landing. Tell them you have already landed and need an appointment. Have the zip code of the Service Center you are interested in handy.
Also, I found another Service Canada when one was able to get a SIN by doing a walk-in at 7:30 and walking out with SIN at 10am:
Service Canada Centre
5353 Dundas St W, Etobicoke, ON M9B 6H8
+1 800-622-6232
https://g.co/kgs/gP8t5J
The above is through the telegram group I am a member of. Two people vouched for this location.