You will find a number of conflicting stories including the rank of the marine and when/where he was contacted. This is typical reporter laziness/inaccuracy. The story is real:
Amputee War Hero U.S. Senator Still Fights for Survival
http://www.defenselink.mil/news/Jan2000/n01272000_20001274.html Cleland's life journey began in June 1967 when he arrived
in Vietnam for duty as a captain in the 1st Air Cavalry
Division. His unit helped lift the 76-day-long enemy siege
on 5,000 Marines at Khe Sanh during the 1968 Tet Offensive.
Cleland recalled being thankful to be alive and unhurt when
his unit was relieved on April 5. But just three days
later, and a month before he'd have rotated home, his luck
ran out after he and his team had unloaded a helicopter.
As the aircraft lifted off, he saw a hand grenade on the
ground. Thinking he'd dropped it, he reached to pick it up
with his right hand. He never made it.
"As the story goes, the guy behind me was peppered with
shrapnel, but he didn't lose any limbs," Cleland said. "He
was crying and saying, 'It's my fault, my fault, my
grenade, my grenade!'" Apparently the soldier had been told
or scared into thinking that loosening the pins on his
grenades would make them easier to pull out in combat. The
pins normally come bent so they don't come loose
accidentally.
"So one of his grenades with the loosened pins fell off his
web gear and blew me up," said Cleland. "I've had a helluva
time coming to terms with that.
"The explosion blew off my right arm and right leg
instantly and mangled my left leg so badly it had to be
amputated," he said. "I was lucky to survive because my
windpipe was cut, front teeth were knocked out. I was a
bloody mess lying there on the ground -- dying."
"I remember somebody cutting off my uniform and trying to
tie a tourniquet and the screaming for a helicopter
medevac," he said. He fought to stay conscious. "I figured
if I lost consciousness, I wouldn't make it back. I'd lost
a lot of blood. My legs were smoking. I'd been so close to
the grenade that the flash burn had seared the flesh.
That's probably why I didn't bleed to death right there."