Hopefully I can provide you a few answer's to your questions. Please do not alter the table or machine. Your serial number which is found on the back plate shows a production date after 1878 or 89. The principal offices of the Howe Machine Co. were world wide. Vienna's office was located at 15 Karnthner-ring. Hamburg was Itr. Branswiete, No.13. Having the shuttle and two bobbins is gold, are these are often misplaced.
There is a lot of information on the Internet regarding the history of this machine as well as how to thread it for sewing.
Here is a link to assist you in dating the machine:
https://www.fiddlebase.com/american-...ing-howe-amas/
There area several knowledgeable people who can assist you in restoring your machine. Enjoy!
http://www.sewmuse.co.uk/howe.htm