i've never seen suntour shifters quite like that. if they're like other, more common suntour shifters, that bracket you say is loose should fit snuggly and rest in place within the clamp. if it doesn't, i will guess either it or the clamp is broken.

if the shifter is tight, that loose bracket may not be an issue.

better suntour shifters can be had for $5 - $20 depending on the resources you have available (co-op, craigs, ebay, etc.).