NO you don't but it may be easier to maintain
In any case if you don't want to create the table just use:
declare
@start datetime
, @end datetime
select
@start = '20040306'
, @end = '20040326'
select datediff (wk, @start, @end)-1
+ case when datepart (dw, @end) >= 6 then 1 else 0 end
+ case when datepart (dw, @start) <= 6 then 1 else 0 end as NoFridays