I'm probably late to the game here, but just had my first 4505 sausage sandwich at Ferry Plaza today at lunch. I was heading towards Roli Roti to see what magical sandwich he was putting out, and was diverted on the way by the "Thai Sausage Sandwich" sign at 4505.
Wow. It was worth the stop. A perfect bun (not sure of origin, but maybe a bit between a brioche and levain, if that's not contradictory - nice heft and density), some "thai" sauce, chunks of fresh watermelon, sliced red onion (a little) and some (Thai?) basil. Wow. At $7, it seemed like a good deal, especially compared to the tiny Namu "korean tacos" at the next stall.
I saw the offer of the "Golden Dog" and one other sausage, but this perfectly coiled sausage with the complementary cool/sweet watermelon, a little bit of spice from the basil, and the sauce and bun were a perfectly executed interplay of flavor.
Alas, they said it's today only, but I will be back next Thursday to see what the SOD (sausage of the day) is. I'm lucky - I work right across the street from Ferry Plaza...
I saw, but didn't try, the many bags of their chicharones - I am tempted to walk back over after reading about them!