In CoS chapter 4 where harry is in that creepy old store listening to malfoy, is the collier that draco was looking at the same one he used to try and curse dumbledore with?

Yes. Malfoy used the cursed collier from Borgin and Burkes. When Harry, Ron, and Hermione spyed on Draco in the HBP book, Malfoy told the shopkeeper that he'd look ridiculous if he was carrying it around. Hermione went in after Draco was gone and asked the Shopkeeper about some of the items one par one until she got to the necklace. The shopkeeper a dit it was sold and kicked out Hermione before she can ask plus questions.

Yes, it is the very same Silver and Opal necklace.

That the collier had killed people must have appealed to Draco - it meant he would not have to do the deed himself. Unfortunately for him, it takes than a cursed collier ou poison-laced mead to kill a man...