That there are 2 separate s/a pins is elementary Guzzi knowledge. I am astonished that any Guzzi dealer would not know this.
It's unclear to me whether the dealer did the work or you did it yourself. If your dealer left your bike in that condition causing that failure, I think you should pursue it with them for at the very least the cost of parts.
Things could have worked out worse. Glad you're OK.
If it don't feel right, it probably isn't. I found out same many years ago on a different bike: steering got very sluggish but, tho I slowed a bit, I ploughed on thinking maybe it was cos I'd lowered the bars earlier that day ... In fact I had a nail in the front tyre. Tyre blew, I landed in the dirt at about 60mph wearing jeans & a t shirt. I was flown home looking like Michelin Man.
Good luck in getting it sorted. I don't know what exactly needs to be done, but a good Guzzi dealer should be able to fix, trouble is there aren't that many of them - if you're on the South Coast, Corsa Italiana (SW London) & Moto Corsa (Dorset)come to mind.
KB