My boys are 2 years and 3 months old and 9 months old...I found that our toddler would do the same thing. I actually think you are doing the right thing in paying a bit more attention to your boy... after all, if you look at things from his point of view, he is still only little, a baby himself really, and he was THE baby of the house until your girl came along.
I don't think it will have to cause issues later on, especially if you take care of his needs before baby's so that he doesn't feel like he's been ousted.
When our baby was newborn, and even now, I made sure that I fed our toddler first, and didn't try to make him wait to eat or for his drink as he is too small to understand. Now, he plays nicely with his baby brother and it helped stop his clinging to me when I made sure to include him as much as possible while I was doing things for baby, like when I change baby, he would sit and talk to his brother, or he would help me run their bath and I bathe thwm together.
It was also really important for me to make time just for him, so instead of fussing over the house work or doing other things when baby has his naps (he has two a day), I make sure that my toddler and I have quality time together, drawing, playing with his toys or even just sitting and watching one of his movies... I also take him to playgroup once a week, and leave baby at home with his Dad, this gives us Mum/Son time without me being distracted by baby.
I'm not sure if any of this has helped you, but my own opinion is that he just wants to feel secure and as a little guy this is the only way he can express this... good luck, hope it all works out. :-)
Peace, Love, Happiness and Hugs.MumBum of three boys. XXX