different results in to_date()

Hi, I just noticed a difference in output with the to_date() function
between 8.3.7 and 8.4.B2.

Running the following query on PG 8.3.7

select

to_char(2009,'9999') as year,

to_char(3,'09') as month,

to_date(to_char(2009,'9999')||to_char(3,'99') ,'YYYYMM') as method1,

to_date(to_char(2009,'9999')||'-'||to_char(3,'09') ||
'-01','YYYY-MM-DD') as method2

results in:

year, month, method1, method2

" 2009";" 03";"2009-03-01";"2009-03-01"

Running exactly the same query on PG 8.4.B2 gives:

year, month, method1, method2

" 2009";" 03";"0200-09-01";"2009-03-01"

PG 8.3.7 "method1" = "2009-03-01"

PG 8.4.B2 "method1" = "0200-09-01"

Both databases were on the same machine - Fedora 10 - 32bit (GCC 4.3.2).
Server configured for Australian timezone/usage.

I realize I should have slapped a trim() around the to_char(), but
thought it worth noting the difference anyway.

Cheers,

Jeremy.