Barry, I've had a number of trailers with the old coupler. The part in front looks scary, but it's very secure. The part you have to be concerned about is wear in the 'latch' (the cylindrical and angled bottom part of the mechanism you flip down) in the back of the coupler that locks the coupler to the ball. I just acquired two '53 Flying Clouds (one for a friend) and towed them 200 miles and 450 miles respectively with the old couplers. There is no way (that I know of) to replace just the coupler lock mechanism. The jack was bad on my Flying Cloud, so rather than mess with grinding off the rivets and then trying to retrofit a new jack, I had the entire coupler replaced with a 'bulldog' style coupler. The coupler AND jack came to an astounding $55 from my local RV parts store, and I gave a welder friend $75 to cut the old one off and weld the new one on. If you suspect you have a worn coupler, replacement is the answer.
I had a fiberglass trailer with a worn coupler when I picked it up last spring and it jumped off the ball on me at 65mph. NOT a fun experience! Unfortunately, I DIDN'T do my own ritual testing when I picked it up as I was in a hurry... I knew better, and left anyway...
The only way I know of (and you should do this each time you hook up) to test your connection is to jack the tongue up with the coupler locked. The rear end of the car should rise smoothly a few inches with the trailer tongue when you raise the tongue jack. If the ball slips out of the coupler, it's time to park it until you can get the coupler replaced. As long as they stay connected, you're fine.
AIR 2053 Current: 2006 Born Free 32 RQ Kodiak Chassis, & 1995 Coachmen B-van
Former Airstreams: 1953 Flying Cloud, 1957 Overlander, 1961 Bambi, 1970 Safari Special, 1978 Argosy Minuet, 1985 325 Moho, 1994 Limited 34' Two-door, 1994 B190 "B-Van"