Hello
It doesn't look right to me.
As Andy says be careful for the time being.
You have two choices - buy a modular toolrest such as the sorby which is first class (as Philip suggests. This comprises a toolpost (you'll have to measure the diameter of yours, and a then you can buy a range of rests - a 9" straight bar, 6" bar, 4" bar plus others if the fancy takes you.
Or, and this would be my first thought - create an account on the Record website
http://www.recordpower.co.uk/Then raise a support request.
I have done this a number of times with queries or spares requests from record and found their service first class. Hopefully this will get it resolved.
Finally, if you didn't get it Direct from record have you gone back to the supplier? Just having a look at the record site I wonder perhaps if you;ve got the banjo/rest for the CL3/4 which has a greater diameter over the bed?
Or and definitely finally why don;t you take your banjo and rest to a store if you have one nearby and compare with another one?
Let us know how you get on.
Cheers Dave