Could be.
Or it could be a cold.
According to Google:
"Boys do experience voice change during puberty, and the change can happen anywhere between the ages of 10 and 15. Typically, voice change begins somewhere around age 12 or 13, or during the middle school years."
A need to start using a deodorant somewhere in 4th or 5th grade is one common first step but they don't come in any particular order.
Additional:
It's great you and your son communicate.
As kids grow, there are lots of changes - your husband should be familiar with them - after all he went through puberty male version himself.
My husband has hairy legs - from knees to ankles he's a furry guy - and our son takes after him - they both have great legs for kilts but they aren't inclined to wear them.
Armpit hair too - that's why he prefers a speed stick deodorant instead of a roll on because the hair can get pulled with a roll on.
There are great books on the subject - if you have questions and your husband (or father) isn't available then read some before you hand them off to your son.
They cover this stuff in health class in school so he's probably more aware than you are about what's going on.
Gosh I haven't seen 'The Brady Bunch' in ages - I just don't remember the episode you mention.