Why not just go back to the dealer and get the missing parts? The igniter should be held in place so the spark gag is fixed. If the dealer is too far just call Suburban Tech support, 423 775 2131, and see if they will mail you the part. Suburban is not a customer oriented company but you can get through if you stay with it.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles