which top sash guide for this channel balance?

Hi, there,
I bought this channel balances already (Series 351-25, option 2430). They work fine. But I need to replace several corresponding top sash guides. My existing ones have a weird shape which I can't find any on your website matching the exact shape.
I originally thought mine was broken 18-159P. But when I have 18-159P in hand, it appeared to be slightly different. They have different positions for the lower screw hole. So I start to wonder if previous people installed the wrong top guides.
Please help!