The answer is "NOT really"!
Designer job is different compare to others.
Most of the company're more interest ur portfolio then ur diploma,
they dun care how good u were in sch, they just concern how can u
contribute in his company.
My case:
1997 April - I only got my O level cert(very bad result), but I
found an illustration job (part time basic), I completed some
education books(for primary sch) which some are sold in Popular
book store. My ex company = "Index Educational Pte Ltd".
1997 July - Find a better pay company, working as an FA artist, do
a very basic printing job, self taught all the graphic sofware,
always ask, learn from my senior.
1998 Oct - Join a publishing company as a junior graphic designer,
company sponsor me to study part time diploma course in NAFA(this
sch suck), later transfer to Lasalle(good sch, but feel boring to
do homework, after 1 semester, I quit), concentrade my work, keep
all my job portfolio.
2000 Jan - Change job to other design house, that time I bring some
of my best portfolio for interview, within 2 week, I found a new
job.
2003 Feb - Feeling is time to take some rest, quit my job, go to
NYP study animation, bcos of my bad O lvl result, I join the SAE
program, from total amount of 400+ applicants, SDN only select 40
ppl for interview, from there choose the best 20 ppl, I'm not the
best, but very lucky I be selected.
During the sch days, sometimes i still received some freelance job
from my ex company.
2006 - Completed the course, feel lazy to work for ppl, setup my
own company, be my own boss, what ever design job i have, get
freelancer to work for me, I'm just responsible to get more
business, earn $$$.
Old already, very tired to do design again 
p/s: Believe me, last time I work for 1 company, my collegue got
diploma, but his salary lower than me, so portfolio very important
for the designer.
sry for my broken English, I dun like to studies, that's y I go for
art.
