yes....
you should weld it on..... or have it welded on...
get a steel an fitting....
weld it on..... then with oil still in the pan drill it out.....
the oil on the back side with flush the chips out..... ive done about 6 oil pans like this with no problems....
one time i burned a small pin hole throught the pan tho...... i had to wait for the oil to drain at that point.... it sucked.