No - it's not. That is not what a subjunctive is.
It's easier to get a feel for the subjunctive than explain it - although the Wikipedia article on the subjunctive mood is good.
The subjunctive is most often found in "optatives" - ie in phrases expressing a wish.
Go raibh maith agat - raibh is present subjunctive. That it may be good with you.
Having said that, most uses of the subjunctive are quite rare, and go raibh is by far the most common. If you look at my conjunction tables at
http://www.corkirish.com/wordpress/verb-conjugation/taim , you will see that there are forms like go rabhad, go rabhaid siad etc - these are exceedingly rare. I have an electronic copy of Mo Sgéal Féin, Séadna and Matthew's and Mark's Gospels - all by PUL - and there is not a single instance of "rabhad". Go raibh mé in the CO - but still rare.
Non-optative uses - these are for things other than "wishes" - and in southern Irish the present subjunctive is frequently replaced by the future anyway. (let's forget the past subjunctive for the purposes of this post)
Note also that in the first conjugation, the subjunctive is very similar to the future, dropping the f - and the pronunciation is often the same - so it can be a moot point whether the subjunctive has been used or not.
go nglanfad=future
go nglanad=present subjunctive, with a slight h in the pronunciation
There are certain constructions that call for the subjunctive (or future where that replaces it)
chun go
ionnas go
sara (sula)
go
nó go
nár (in the negative)
Examples from Séadna:
Cead agus cúnamh agus caoi do thabhairt dom ar an mbithiúnach do leanúint agus d’fhiach chun go mbeiread air? (chun go mbeiread - until I catch him)
Ní thráchtfad ar a h-ainm leat chun go mbéidh a fhios agam an bhfuilir ollamh agus ceapaithe ar phósadh (until I know you are ready and intending on marriage). This is an example where the future has replaced the subjunctive, but I understand that with the verb táim the subjunctive is only used for optative uses.
Níl uaimse anois ach slán a fhágáilt ag bhur sagart agus agaibh go léir sara dtugad aghaidh ar Bhaile-i-bhfad-síos (before I make for Baile i bhfad sios)
In the first example, you could say sara mbeirfead, and in the third example sara dtiocfad.
Another example: fan go dtagad ansan (wait till I get there) As I don't think the subjunctive of táim is used in non-optative senses, it would be: fan go mbéidh mé ansan (I also don't think the synthetic forms are used much in the first and second persons singular of the future)
The present subjunctive is largely a non-subject - it is simply normally not used.